Celestron 11007 User`s guide

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Celestron 11007 User`s guide | Manualzz
#11007 / #11008 / #11009
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>> www.celestron.com
Congratulations on your purchase of the Celestron CPC DeluxeHD
telescope! The CPC DeluxeHD combines Celestron’s newly designed
CPC Computerized mount with its new EdgeHD optical system. The
CPC series uses GPS (Global Positioning System) technology to take the
sky. Simple and easy to use, the CPC with its SkyAlign sky modeling
so advanced that once you turn it on, the integrated GPS automatically
pinpoints your exact coordinates. No need to enter the date, time,
longitude and latitude or even know the name of a single star in the sky.
Take time to read through this manual before embarking on your
become familiar with your CPC, so you should keep this manual handy
until you have fully mastered your telescope’s operation. The CPC hand
control has built-in instructions to guide you through all the alignment
procedures needed to have the telescope up and running in minutes. Use
the hand control. The manual gives detailed information regarding each
step as well as needed reference material and helpful hints guaranteed to
make your observing experience as simple and pleasurable as possible.
if you are more experienced, you will appreciate the comprehensive
level you are starting out, the CPC will unfold for you and your friends all
the wonders of the Universe.
Your CPC telescope is designed to give you years of fun and rewarding
observations. However, there are a few things to consider before using
your telescope that will ensure your safety and protect your equipment.
Some of the many standard features of the CPC DeluxeHD include:
Ȉ †‰‡‘’–‹…ƒŽ•›•–‡
Ȉ –‡‰”ƒ–‡†
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fork arm
Ȉ ƒ–ƒ„ƒ•‡ƤŽ–‡”Ž‹‹–•ˆ‘”…”‡ƒ–‹‰…—•–‘‘„Œ‡…–Ž‹•–•
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performance features!
The CPC DeluxeHD’s features combined with Celestron’s legendary
optical systems give amateur astronomers the most sophisticated and
easy to use telescopes available on the market today.
Ȉ ‡˜‡”Ž‘‘†‹”‡…–Ž›ƒ––Š‡—™‹–Š–Š‡ƒ‡†
Ȉ ‡˜‡”—•‡›‘—”–‡Ž‡•…‘’‡–‘’”‘Œ‡…–ƒ‹ƒ‰‡‘ˆ–Š‡—
telescope and any accessories attached to it.
Ȉ ‡˜‡”—•‡ƒ‡›‡’‹‡…‡•‘Žƒ”ƤŽ–‡”‘”ƒ‡”•…Š‡Ž™‡†‰‡Ǥ
sunlight to pass through to the eye.
Ȉ ‡˜‡”Ž‡ƒ˜‡–Š‡–‡Ž‡•…‘’‡—•—’‡”˜‹•‡†ǡ‡‹–Š‡”™Š‡
children are present or adults who may not be familiar
with the correct operating procedures of your telescope.
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>> www.celestron.com
͟Ǥ ‹†‡”•…‘’‡—‹…‡Ž‡ƒ•‡”ƒ…‡–
͠Ǥ ’–‹…ƒŽ—„‡
͡Ǥ …Š‹†–‘””‡…–‘”‡•
͙͘Ǥ Ž–‹–—†‡‘…‹‰‘„•
͙͙Ǥ ƒ””›‹‰ƒ†Ž‡
Ǥ –‡”ˆƒ…‡‘”–
Ǥ —–‘
The CPC DeluxeHD telescope comes completely pre-assembled and can be operational in a matter of minutes. The CPC and its accessories are
CPC Deluxe 800 HD
203 mm (8”) Edge HD Optics
Focal Length
2032 mm f/10
40 mm - 1.25” (51x)
90° - 1.25”
CPC Altazimuth
2” Stainless Steel
NexRemote Telescope Control
Software with RS-232 cable
Car Battery Adapter
CPC Deluxe 925 HD
CPC Deluxe 1100 HD
235 mm (9.25”) Edge HD Optics
280 mm (11”) Edge HD Optics
2350 mm f/10
2800 mm f/10
23 mm - 2” (102x)
23 mm - 2” (122x)
90° - 2” with 1.25” adapter
90° - 2” with 1.25” adapter
CPC Altazimuth
CPC Altazimuth
2” Stainless Steel
2” Stainless Steel
NexRemote Telescope Control
NexRemote Telescope Control
Software with RS-232 cable
Software with RS-232 cable
Car Battery Adapter
Car Battery Adapter
Start by removing the telescope and tripod from their shipping cartons
carry the telescope by holding it from the lower portion of the fork arm
on the hand control side and from the handle on the opposite side.
Remove all of the accessories from their individual boxes. Remember
to save all of the containers so that they can be used to transport the
telescope. Before attaching the visual accessories, the telescope should
be mounted on the tripod and the tube should be positioned horizontal
to the ground.
Setting up theTripod
tripod must be shipped with the leg support bracket detached so the
tripod legs can collapse. To set up the tripod:
1. Hold the tripod with the head up and the legs pointed toward
the ground.
2. Pull the legs away from the central column until they will not separate
any further. The top of each tripod leg presses against the tripod head
to indicate maximum separation.
͛Ǥ ‡‘˜‡–Š‡–‡•‹‘‘„ǡŽ‘…ƒ–‡†‘–Š‡…‡–”ƒŽ…‘Ž—Ǥ‡‡Ƥ‰—”‡͛Ǧ͙Ǥ
4. Place the leg support bracket over the central rod so that the cups on
the end of each bracket are directly underneath each leg.
5. Rotate the tension knob until the bracket is secure against the tripod
legs. ‘‘–‘˜‡”–‹‰Š–‡Ǥ
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Adjusting theTripod Height
Note: When transporting your telescope, make sure that both
clutches are somewhat loose; this will diminish the load placed on
the worm gear assemblies and protect them from damage.
the height at which the tripod stands:
͙Ǥ ‘‘•‡–Š‡‡š–‡•‹‘…Žƒ’‘‘‡‘ˆ–Š‡–”‹’‘†Ž‡‰•ȋ•‡‡Ƥ‰—”‡͛Ǧ͙ȌǤ
2. Extend the leg to the desired height.
3. Tighten the extension clamp to hold the leg in place.
4. Repeat this process for each of the remaining legs making sure that
the tripod is level when complete.
You can do this while the tripod legs are still folded together.
Remember that the higher the tripod legs are extended, the less stable
you plan on doing photography, the tripod should be set low to ensure
stability. A recommended height is to set the tripod in such a manner
that you can look directly into the eyepiece on the telescope with a
diagonal while seated.
Attaching the CPC to theTripod
The star diagonal is a prism or mirror that diverts the light at a right angle
to the light path of the telescope. This allows you to observe in positions
that are physically more comfortable than if you looked straight through.
To attach the 1.25” star diagonal onto the 8” optical tube:
After the tripod is set up, you are now ready to attach the telescope.
The bottom of the CPC base has three threaded holes that mount to the
tripod head and one hole in the center that goes over the positioning pin
on the tripod head.
1. Place the center hole in the bottom of the telescope base over the
positioning pin in the center of the tripod head.
2. Rotate the telescope base on the tripod head until the three feet on
the bottom of the base fall into the feet recesses on the top of the
tripod head.
1. Turn the set screw on the visual back until its tip no longer extends
into (i.e., obstructs) the inner diameter of the visual back.
3. Thread the three attached mounting bolts from underneath the
tripod head into the bottom of the telescope base. Tighten all
three bolts.
3. Tighten the set screw on the visual back to hold the star diagonal
in place.
You are now ready to attach the visual accessories onto the telescope
optical tube.
Adjusting the Clutches
The CPC has a dual axis clutch system. This allows you to move the
telescope manually even when the telescope is not powered on.
However, both clutches need to be tightened down for the telescope to
be aligned for “GoTo” use. Any manual movement of the telescope will
invalidate your telescope’s alignment.
knob while holding the telescope tube by the rear cell handle. Rotate the
tube upwards until it is level with the ground and tighten the
locking knob.
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2. Slide the chrome portion of the star diagonal into the visual back.
screw on the visual back until the star diagonal rotates freely. Rotate the
diagonal to the desired position and tighten the set screw.
To attach the 2” star diagonal onto the 9.25/11” optical tubes:
1. Remove the visual back from the rear of the tube.
2. Attach the threaded ring of the 2” diagonal to the rear cell of
the telescope.
3. Loosen the thumb screws on the side of the diagonal and remove the
1.25” adapter from the barrel of the diagonal.
the retaining ring that attaches the diagonal to the rear cell. Rotate the
diagonal to the desired position and tighten the retaining ring.
The Eyepiece
star diagonal. To install the eyepiece:
1. Loosen the thumbscrew on the star diagonal so it does not obstruct
the inner diameter of the eyepiece end of the diagonal.
2. Slide the chrome portion of the eyepiece into the star diagonal.
3. Tighten the thumbscrew to hold the eyepiece in place.
To remove the eyepiece, loosen the thumbscrew on the star diagonal
and slide the eyepiece out.
Eyepieces are commonly referred to by focal length and barrel diameter.
The focal length of each eyepiece is printed on the eyepiece barrel.
The longer the focal length (i.e., the larger the number) the lower the
WARNING: If you remove the mounting bracket, do not
completely thread the screws back into the rear cell of the
telescope. The screws may be long enough to obstruct the
movement of, and possibly damage the primary mirror.
Barrel diameter is the diameter of the barrel that slides into the star
diagonal or visual back. The CPC uses eyepieces with a standard 1-1/4”
barrel diameter.
The Finderscope
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Finderscope Installation
͛Ǥ —•Š–Š‡Ƥ†‡”„ƒ…—–‹Ž–Š‡Ǧ‹‰‹••—‰‹•‹†‡–Š‡ˆ”‘–”‹‰‘ˆ
bracket then attached to the rear cell of the telescope. To install
͙Ǥ ‘…ƒ–‡–Š‡Ƥ†‡”•…‘’‡‘—–‹‰„”ƒ…‡–ƒ––ƒ…Š‡†–‘–Š‡„‘––‘
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when looking from the back of the tube.
3. Place the mounting bracket over the two holes of the rear cell as
͜Ǥ •‡”––Š‡•…”‡™•–Š”‘—‰Š–Š‡„”ƒ…‡–ƒ†‹–‘–Š‡”‡ƒ”…‡ŽŽǤ
>> www.celestron.com
Aligning the Finderscope
bracket and a spring loaded pivot screw (located on the left side of the
To make the alignment process a little easier, you should perform this
͙Ǥ Š‘‘•‡ƒ…‘•’‹…—‘—•‘„Œ‡…––Šƒ–‹•‹‡š…‡••‘ˆ‘‡‹Ž‡ƒ™ƒ›ǤŠ‹•
Ȉ ‘…ƒ–‡–Š‡Šƒ†…‘–”‘ŽŠ‘Ž†‡”ƒ†•Ž‹†‡‹–†‘™‹–‘–Š‡•Ž‘–Ž‘…ƒ–‡†
Ȉ —•Š–Š‡…‘‡…–‘”‹–‘–Š‡Œƒ…—–‹Ž‹–…Ž‹…•‹–‘’Žƒ…‡Ǥ
The hand control can now rest in the holder on the fork arm
of the telescope.
Powering the CPC
The CPC can be powered by the supplied 12v car battery adapter or
of this manual).
1. To power the CPC with the car battery adapter, simply plug the round
post into the designated 12v power outlet located on the drive base.
͚Ǥ —”‘–Š‡’‘™‡”–‘–Š‡„›ƪ‹’’‹‰–Š‡Ȁơ•™‹–…ŠǤ
͚Ǥ ‘‹–›‘—”–‡Ž‡•…‘’‡ƒ––Š‡‘„Œ‡…–›‘—•‡Ž‡…–‡†ƒ†…‡–‡”‹–‹–Š‡
main optics of the telescope.
3. Lock the azimuth and altitude clamps to hold the telescope in place.
͜Ǥ Š‡…–Š‡Ƥ†‡”–‘•‡‡™Š‡”‡–Š‡‘„Œ‡…–‹•Ž‘…ƒ–‡†‹–Š‡Ƥ‡Ž†‘ˆ˜‹‡™Ǥ
͝Ǥ †Œ—•––Š‡–Š—„•…”‡™•‘–Š‡Ƥ†‡”„”ƒ…‡–—–‹Ž–Š‡…”‘••Šƒ‹”•ƒ”‡
centered on the target.
(i.e., upside down and reversed from left-to-right). Because of this, it may
take a few minutes to familiarize yourself with the directional change
Attaching the Hand Control
unit has been packaged along with the other telescope accessories and
will need to be plugged in to the drive base of your telescope. The hand
3-10). Your telescope also comes with a hand control holder that must be
attached to the fork arm. To connect the hand control to the fork arm:
>> www.celestron.com
The CPC is controlled by Celestron’s NexStar hand controller designed
a few observing sessions. Below is a brief description of the individual
components of the CPC’s NexStar hand controller:
1. ‹“—‹†”›•–ƒŽ‹•’Žƒ›ȋȌ‹†‘™ǣƒ•ƒ†—ƒŽǦŽ‹‡ǡ͙͞…Šƒ”ƒ…–‡”
display screen that is backlit for comfortable viewing of telescope
information and scrolling text.
2. Ž‹‰ǣ•–”—…–•–Š‡–‘—•‡ƒ•‡Ž‡…–‡†•–ƒ”‘”‘„Œ‡…–ƒ•ƒ
alignment position.
Double Stars
4. ƒ–ƒŽ‘‰‡›•ǣ The NexStar hand control has keys to allow direct
access to each of the catalogs in its database. The hand control
contains the following catalogs in its database:
Common name listing of the brightest stars
in the sky.
Numeric-alphabetical listing of the most
visually stunning double, triple and quadruple
stars in the sky.
Select list of the brightest variable stars with
the shortest period of changing magnitude.
A unique list of some of the most
recognizable star patterns in the sky.
pairs, trios and clusters that are well suited
for CCD imaging with the CPC telescope.
5. ˆ‘ǣ‹•’Žƒ›•…‘‘”†‹ƒ–‡•ƒ†—•‡ˆ—Ž‹ˆ‘”ƒ–‹‘ƒ„‘—–‘„Œ‡…–•
selected from the NexStar database.
͞Ǥ ‘—”ǣ…–‹˜ƒ–‡•–Š‡–‘—”‘†‡ǡ™Š‹…Š•‡‡•‘—–ƒŽŽ–Š‡„‡•–‘„Œ‡…–•
for the current date and time, and automatically slews the CPC to
͟Ǥ –‡”ǣ Pressing Enter allows you to select any of the CPC functions
and accept entered parameters.
8. †‘ǣ Undo will take you out of the current menu and display the
previous level of the menu path. Press Undo repeatedly to get back to
a main menu or use it to erase data entered by mistake.
9. ‡—ǣ Displays the many setup and utilities functions such as tracking
10.…”‘ŽŽ‡›•ǣ Used to scroll up and down within any of the menu lists.
A double-arrow will appear on the right side of the LCD when there
are sub-menus below the displayed menu. Using these keys will scroll
through those sub-menus.
11. ƒ–‡ǣ•–ƒ–Ž›…Šƒ‰‡•–Š‡”ƒ–‡‘ˆ•’‡‡†‘ˆ–Š‡‘–‘”•™Š‡–Š‡
direction buttons are pressed.
12.Ǧ͚͚͛ƒ…ǣ Allows you to interface with a computer and control
the CPC remotely.
Messier – ‘’Ž‡–‡Ž‹•–‘ˆƒŽŽ‡••‹‡”‘„Œ‡…–•Ǥ
NGC – ‘’Ž‡–‡Ž‹•–‘ˆƒŽŽ–Š‡†‡‡’Ǧ•›‘„Œ‡…–•‹–Š‡‡˜‹•‡†
New General Catalog.
Caldwell – …‘„‹ƒ–‹‘‘ˆ–Š‡„‡•–
Planets – All 8 planets in our Solar System plus the Moon and the Sun.
Stars – …‘’‹Ž‡†Ž‹•–‘ˆ–Š‡„”‹‰Š–‡•–•–ƒ”•ˆ”‘–Š‡…ƒ–ƒŽ‘‰Ǥ
Named Stars
Variable Stars
3. ‹”‡…–‹‘‡›•ǣ Allows complete control of the CPC in any direction.
Use the direction keys to move the telescope to the initial alignment
List –‘”“—‹…ƒ……‡••ǡƒŽŽ‘ˆ–Š‡„‡•–ƒ†‘•–’‘’—Žƒ”
lists based on their type and/or common name:
This section describes the basic hand control procedures needed to
operate the CPC. These procedures are grouped into three categories:
Alignment, Setup and Utilities. The alignment section deals with the
section discusses changing parameters such as tracking mode, tracking
of the utilities functions such as PEC, polar alignment and hibernating
the telescope.
be aligned to known positions (stars) in the sky. With this information,
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the telescope can create a model of the sky, which it uses to locate any
with the sky depending on what information the user is able to provide:
›Ž‹‰ uses the internal GPS receiver to acquire all the necessary time/
site information needed for the CPC to create an accurate model of the
sky. Then the user can simply point the telescope to any three bright
star, then the CPC will automatically select and slew to a second star
for alignment. ™‘Ǧ–ƒ”Ž‹‰‡– requires the user to identify and
manually slew the telescope to the two alignment stars. ‡Ǧ–ƒ”Ž‹‰
to one known star. Although not as accurate as the other alignment
’Žƒ‡–•ƒ†‘„Œ‡…–•‹Ž–ƒœ‹—–Š‘†‡Ǥ‘Žƒ”›•–‡Ž‹‰ will display
–Š‡–‡Ž‡•…‘’‡Ǥ‹ƒŽŽ›ǡ‘”–Šƒ†‘—–Š alignments are designed
to assist you in aligning the CPC when polar aligned using an equatorial
wedge. Each alignment method is discussed in detail below.
“Altazimuth” or “Alt-Az” refers to a type of mounting that allows
a telescope to move in both altitude (up and down) and azimuth
(left and right) with respect to the ground. This is the simplest
form of mounting in which the telescope is attached directly to a
tripod without the use of an equatorial wedge.
SkyAlign must be used with the telescope mounted in altazimuth. With
SkyAlign, the GPS receiver links with and acquires information from 3 of
the orbiting GPS satellites. With this information, the built-in GPS system
calculates the scope’s location on Earth with an accuracy of a few meters
and calculates universal time down to the second. After quickly making
all these calculations and automatically entering the information for you,
the user simply needs to aim the telescope to any three bright celestial
it is not necessary to know the name of the stars that you are aiming at.
You may even select a planet or the Moon. The CPC is then ready to start
Before the telescope is ready to be aligned, it should be set up in an
attached and lens cover removed as described in the Assembly section of
the manual. To begin SkyAlign:
͙Ǥ ‘™‡”‘–Š‡„›ƪ‹’’‹‰–Š‡•™‹–…ŠŽ‘…ƒ–‡†‘–Š‡…‘–”‘Ž’ƒ‡Ž
control display will say CPC Ready. Press ENTER to choose SkyAlign
options and the scrolling text and automatically begins Sky Align.
͚Ǥ …‡Sky Align has been selected, the hand control will display “Enter
will display either the current time or the time when you last used the
telescope. The GPS will quickly link up and display the current date,
and manually updating the time/site information. Press ENTER to
accept the time/site information downloaded from the GPS.
3. The hand control will display a message reminding you to level the
tripod if you already haven’t done so. Press ENTER to continue.
4. Use the arrow buttons on the hand control to slew (move) the
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͝Ǥ ˆ–Š‡Ƥ†‡”•…‘’‡Šƒ•„‡‡’”‘’‡”Ž›ƒŽ‹‰‡†™‹–Š–Š‡–‡Ž‡•…‘’‡–—„‡ǡ
eyepiece. The CPC will ask that you center the bright alignment star
͞Ǥ ‘”–Š‡•‡…‘†ƒŽ‹‰‡–‘„Œ‡…–ǡ…Š‘‘•‡ƒ„”‹‰Š–•–ƒ”‘”’Žƒ‡–ƒ•ˆƒ”
͟Ǥ ‡’‡ƒ––Š‡’”‘…‡••ˆ‘”–Š‡–Š‹”†ƒŽ‹‰‡–•–ƒ”ǤŠ‡–Š‡–‡Ž‡•…‘’‡
A Few Words on GPS:
Tips for Using SkyAlign
Remember the following alignment guidelines to make using SkyAlign
as simple and accurate as possible.
Ȉ ‡•—”‡–‘Ž‡˜‡Ž–Š‡–”‹’‘†„‡ˆ‘”‡›‘—„‡‰‹ƒŽ‹‰‡–ǤŠ‡–‹‡Ȁ
site information along with a level tripod will help the telescope
better predict the available bright stars and planets that are above
the horizon.
Ȉ ‡‡„‡”›Ž‹‰†‘‡•‘–…ƒ”‡™Š‡”‡–Š‡‘’–‹…ƒŽ–—„‡‹•
pointed at the beginning of the alignment. So to make the
alignment process even faster, it is acceptable to move the
clutches. However the following alignment stars still need to be
found and centered using the hand control.
Ȉ ‡‡„‡”–‘•‡Ž‡…–ƒŽ‹‰‡–•–ƒ”•–Šƒ–ƒ”‡ƒ•ˆƒ”ƒ’ƒ”–‹–Š‡•›
may result in a failed alignment.
Ȉ ‘ǯ–™‘””›ƒ„‘—–…‘ˆ—•‹‰’Žƒ‡–•ˆ‘”•–ƒ”•™Š‡•‡Ž‡…–‹‰
to the planets, the hand control has over 80 bright alignment stars
to choose from (down to 2.5 magnitude).
Ȉ ‘”–Š‡„‡•–’‘••‹„Ž‡’‘‹–‹‰ƒ……—”ƒ…›ǡƒŽ™ƒ›•…‡–‡”–Š‡
the GoTo Approach (by default this will be using the up arrow button
and the right arrow button). Approaching the star from this
direction when looking through the eyepiece will eliminate much
of the backlash between the gears and assure the most accurate
alignment possible.
AutoTwo-Star Align
As with SkyAlign, Auto Two-Star Align downloads all the necessary time/
received, the CPC will prompt you to slew the telescope and point at
one known star in the sky. The CPC now has all the information it needs
to automatically choose a second star that will assure the best possible
second alignment star to complete the alignment. With the CPC set up
outside with all accessories attached and the tripod leveled, follow the
steps below to align the telescope:
͙Ǥ …‡–Š‡‹•’‘™‡”‡†‘ǡ”‡••–‘„‡‰‹ƒŽ‹‰‡–Ǥ
2. Use the Up and Down scroll keys (10) to select Auto Two-Star Align
and press ENTER.
Two-Star Alignment
With the two-star alignment method, the CPC requires the user to know
the positions of two bright stars in order to accurately align the telescope
star alignment procedure:
͙Ǥ …‡–Š‡‹•’‘™‡”‡†‘ǡ—•‡–Š‡ƒ†•…”‘ŽŽ‡›•ȋ͙͘Ȍ–‘
select Two-Star Align, and press ENTER.
2. Press ENTER to accept the time/site information displayed on the
display, or wait until the telescope has downloaded the information
from the GPS satellites.
3. The SELECT STAR 1 message will appear in the top row of the display.
4. CPC then asks you to center in the eyepiece the alignment star you
selected. Use the direction arrow buttons to slew the telescope to the
ENTER when centered.
͝Ǥ Š‡ǡ…‡–‡”–Š‡•–ƒ”‹–Š‡‡›‡’‹‡…‡ƒ†’”‡••
In order to accurately center the alignment star in the eyepiece,
centering. This is done by pressing the RATE key (11) on the hand
controller then selecting the number that corresponds to the
speed you desire. (9 = fastest, 1 = slowest).
͞Ǥ ™‹ŽŽ–Š‡ƒ•›‘—–‘•‡Ž‡…–ƒ†…‡–‡”ƒ•‡…‘†ƒŽ‹‰‡–•–ƒ”
a good distance away from one another. Stars that are at least 40º to
than stars that are close to each other.
3. The hand control will display the last time and location information
that was entered or downloaded from the GPS. Use the Up and
Down buttons to scroll through the information. Press ENTER to
edit the information.
read Alignment Successful, and you should hear the tracking motors
turn-on and begin to track.
4. The display will now prompt you to select a bright star from the
on the keypad) to scroll to the desired star and then press ENTER.
would for the Two-Star Align procedure. However, instead of slewing to
two alignment stars for centering and alignment, the CPC uses only one
star to model the sky based on the information given. This will allow you
altazimuth in any part of the sky.
5. Use the arrow buttons to slew the telescope to the star you selected.
͞Ǥ ƒ•‡†‘–Š‹•‹ˆ‘”ƒ–‹‘ǡ–Š‡™‹ŽŽƒ—–‘ƒ–‹…ƒŽŽ›†‹•’Žƒ›–Š‡‘•–
suitable second alignment star that is above the horizon. Press ENTER
reason you do not wish to select this star (perhaps it is behind a tree
or building), you can either:
Ȉ ”‡••–Š‡„—––‘–‘†‹•’Žƒ›–Š‡‡š–‘•–•—‹–ƒ„Ž‡•–ƒ”
for alignment.
Ȉ •‡–Š‡ƒ†•…”‘ŽŽ„—––‘•–‘ƒ—ƒŽŽ›•‡Ž‡…–ƒ›•–ƒ”
you wish from the entire list of available stars.
will ask you to use the arrow buttons to align the selected star with the
press ENTER. The display will then instruct you to center the star in the
accept this star as your second alignment star. When the telescope has
been aligned to both stars the display will read Alignment Success, and
One-Star Align
͙Ǥ ‡Ž‡…–‡Ǧ–ƒ”Ž‹‰ˆ”‘–Š‡ƒŽ‹‰‡–‘’–‹‘•Ǥ
2. Press ENTER to accept the time/site information displayed on the
display, or wait until the telescope has downloaded the information
from the GPS satellites.
3. The SELECT STAR 1 message will appear in the top row of the display.
Use the Up and Down scroll keys (10) to select the star you wish to use
4. The CPC then asks you to center in the eyepiece the alignment star
you selected. Use the direction arrow buttons to slew the telescope
Press ENTER when centered.
͝Ǥ Š‡ǡ…‡–‡”–Š‡•–ƒ”‹–Š‡‡›‡’‹‡…‡ƒ†’”‡••
͞Ǥ …‡‹’‘•‹–‹‘ǡ–Š‡™‹ŽŽ‘†‡Ž–Š‡•›„ƒ•‡†‘–Š‹•‹ˆ‘”ƒ–‹‘
and display Alignment Successful.
>> www.celestron.com
Note: Once a One-Star Alignment has been done, you can use
the Re-alignment feature (later in this section ) to improve your
telescope’s pointing accuracy.
Solar System Align
Solar System Align is available in alt-az mode (scope mounted directly
on the tripod) and equatorial mode (scope mounted on a wedge).
Solar System Align is designed to provide excellent tracking and GoTo
align the telescope with the sky. Solar System Align is a great way to
align your telescope for daytime viewing as well as a quick way to align
the telescope for night time observing.
Never look directly at the Sun with the naked eye or
Permanent and irreversible eye damage may result.
1. Select Solar System Align from the alignment options.
2. Press ENTER to accept the time/site information displayed on the
display, or wait until the telescope has downloaded the information
from the GPS satellites.
͛Ǥ Š‡‡••ƒ‰‡™‹ŽŽƒ’’‡ƒ”‹–Š‡–‘’”‘™‘ˆ–Š‡
display. Use the Up and Down scroll keys (10) to select the daytime
͜Ǥ Š‡–Š‡ƒ••›‘—–‘…‡–‡”‹–Š‡‡›‡’‹‡…‡–Š‡ƒŽ‹‰‡–‘„Œ‡…–
you selected. Use the direction arrow buttons to slew the telescope to
ENTER when centered.
͝Ǥ Š‡ǡ…‡–‡”–Š‡‘„Œ‡…–‹–Š‡‡›‡’‹‡…‡ƒ†’”‡••
and display Alignment Successful.
Tips for Using Solar System Align
Ȉ ‘”•ƒˆ‡–›’—”’‘•‡•ǡ–Š‡—™‹ŽŽ‘–„‡†‹•’Žƒ›‡†‹ƒ›‘ˆ–Š‡Šƒ†
Menu. To allow the Sun to be displayed on the hand control,
do the following:
4-3). Based on this information the CPC will automatically slew to two
selected alignment stars to be centered and aligned. To use EQ
1. Select EQ North or South Align from the alignment options and
press ENTER
2. Press ENTER to accept the time/site information displayed on the
display, or wait until the telescope has downloaded the information
from the GPS satellites.
3. Select EQ AutoAlign method and press ENTER
4. Use the up and down arrow buttons to move the telescope tube
upwards until the altitude index markers are aligned. The altitude
5. Use the left and right arrow buttons to move the telescope base
until the fork arms are horizontally parallel and the tube is pointing
towards the Meridian.
͞Ǥ ƒ•‡†‘–Š‹•‹ˆ‘”ƒ–‹‘ǡ–Š‡™‹ŽŽƒ—–‘ƒ–‹…ƒŽŽ›†‹•’Žƒ›–Š‡‘•–
suitable alignment stars that are above the horizon. Press ENTER to
reason you do not wish to select one of these stars (perhaps it is
behind a tree or building), you can either:
Ȉ ”‡••–Š‡„—––‘–‘†‹•’Žƒ›–Š‡‡š–‘•–•—‹–ƒ„Ž‡•–ƒ”
for alignment.
Ȉ •‡–Š‡ƒ†•…”‘ŽŽ„—––‘•–‘ƒ—ƒŽŽ›•‡Ž‡…–ƒ›•–ƒ”
you wish from the entire list of available stars.
͟Ǥ –Š‡ƒ••›‘—–‘…‡–‡”‹–Š‡‡›‡’‹‡…‡–Š‡ƒŽ‹‰‡–‘„Œ‡…–›‘—
selected. Use the direction arrow buttons to slew the telescope to
ENTER when centered.
͠Ǥ Š‡ǡ…‡–‡”–Š‡‘„Œ‡…–‹–Š‡‡›‡’‹‡…‡ƒ†’”‡••
͡Ǥ …‡›‘—’”‡••–Š‡
complete alignment.
͙Ǥ ”‡••–Š‡„—––‘—–‹Ž–Š‡†‹•’Žƒ›”‡ƒ†•Dz‡ƒ†›dzǤ
2. Press the MENU button and use the Up and Down keys to select the
Utilities Menu. Press ENTER.
3. Use the UP and Down keys to select Sun Menu and press ENTER.
4. Press ENTER again to allow the Sun to appear on the hand
control display.
The Sun can be removed from the display by using the same procedure
as above.
Ȉ ‘‹’”‘˜‡–Š‡–‡Ž‡•…‘’‡’‘‹–‹‰ƒ……—”ƒ…›ǡ›‘—…ƒ—•‡–Š‡
Re-Align feature as described below.
EQ North / EQ South Alignment
EQ North and EQ South Alignments assist the user in aligning the
telescope when polar aligned on an optional equatorial wedge. Similar
to the Altazimuth alignments described earlier, the EQ alignments gives
Star alignment or Solar System alignment.
EQ AutoAlign
The EQ AutoAlign uses all the same time/site information as the Alt-Az
alignments, however it also requires you to position the tube so that the
>> www.celestron.com
EQTwo-Star Align
The EQ Two-Star Align follows most of the same steps as the Alt-Az
Two-Star Align. This alignment method does not require the user to align
the altitude index markers or point towards the Meridian, but it does
require the user to locate and align the telescope on two bright stars.
When selecting alignment stars, it is best to choose stars that, a) have a
large separation in azimuth and b) both are either positive or negative in
EQ Two-Star alignment.
EQ One-Star Align
however it only relies on the alignment of one star to align the telescope.
EQ Two-Star Align, but only using one star.
from any of the catalogs in the CPC’s extensive database. The hand
control has a key (4) designated for each of the catalogs in its database.
EQ Solar System Align
equatorially align the telescope for daytime use. To align your telescope
EQ Two-Star Align section.
CPC Re-Alignment
The CPC has a re-alignment feature which allows you to replace either of
be useful in several situations:
Ȉ ˆ›‘—ƒ”‡‘„•‡”˜‹‰‘˜‡”ƒ’‡”‹‘†‘ˆƒˆ‡™Š‘—”•ǡ›‘—ƒ›‘–‹…‡
that your original alignment stars have drifted towards the west
considerably. (Remember that the stars are moving at a rate of 15º
every hour). Aligning on a new star that is in the eastern part of the
that part of the sky.
Ȉ ˆ›‘—Šƒ˜‡ƒŽ‹‰‡†›‘—”–‡Ž‡•…‘’‡—•‹‰–Š‡‡Ǧ–ƒ”‘”‘Žƒ”
System alignment method, you can use re-align to align to
accuracy of your telescope without having to re-enter addition
To replace an existing alignment star with a new alignment star:
͙Ǥ ‡Ž‡…––Š‡†‡•‹”‡†•–ƒ”ȋ‘”‘„Œ‡…–Ȍˆ”‘–Š‡†ƒ–ƒ„ƒ•‡ƒ†•Ž‡™–‘‹–Ǥ
͚Ǥ ƒ”‡ˆ—ŽŽ›…‡–‡”–Š‡‘„Œ‡…–‹–Š‡‡›‡’‹‡…‡Ǥ
͛Ǥ …‡…‡–‡”‡†ǡ’”‡••–Š‡„—––‘—–‹Ž›‘—ƒ”‡ƒ––Š‡ƒ‹‡—Ǥ
4. With CPC Ready†‹•’Žƒ›‡†ǡ’”‡••–Š‡
5. The display will then ask you which alignment star you want to replace.
͞Ǥ ”‡••
database that have common names or types. Each list is broken down
When scrolling through a long list of objects, holding down either
the UP or DOWN key will allow you to scroll through the catalog
at a rapid speed.
Pressing any of the other catalog keys (M, CALD, NGC or STAR) will
display a blinking cursor below the name of the catalog chosen. Use
“M” key and enter “042”.
four digits are entered, the hand control will automatically list all the
from the following options:
Ȉ ”‡••–Š‡‡›ǤŠ‹•™‹ŽŽ‰‹˜‡›‘——•‡ˆ—Ž‹ˆ‘”ƒ–‹‘ƒ„‘—––Š‡
Ȉ ”‡••–Š‡‡›ǤŠ‹•™‹ŽŽƒ—–‘ƒ–‹…ƒŽŽ›•Ž‡™–Š‡–‡Ž‡•…‘’‡–‘
Caution: Never slew the telescope when someone is looking into
the eyepiece. The telescope can move at fast slew speeds and may
hit an observer in the eye.
If you manually enter an object that is below the horizon, CPC will
notify you by displaying a message reminding you that you have
selected an object outside of your slew limits (see Slew Limits in the
Scope Setup section of the manual). Press UNDO to go back and
select a new object. Press ENTER to ignore the message and continue
the slew.
alignment. After the telescope is powered on, pressing any of the
>> www.celestron.com
The CPC can locate all 8 of our solar systems planets plus the Sun and
Moon. However, the hand control will only display the solar system
planets, press the PLANET key on the hand control. The hand control will
Ȉ •‡–Š‡Up and Down keys to select the planet that you wish
to observe.
Ȉ ”‡••–‘ƒ……‡••‹ˆ‘”ƒ–‹‘‘–Š‡†‹•’Žƒ›‡†’Žƒ‡–Ǥ
Ȉ ”‡••–‘•Ž‡™–‘–Š‡†‹•’Žƒ›‡†’Žƒ‡–Ǥ
To allow the Sun to be displayed as an option in the database, see Sun
Menu in the Utilities section of the manual (pg. 15).
The CPC includes a tour feature which automatically allows the user
in which you are observing. The automatic tour will display only those
‘„Œ‡…–•–Šƒ–ƒ”‡™‹–Š‹›‘—”•‡–ƤŽ–‡”Ž‹‹–•ȋ•‡‡Filter Limits in the Scope
Ȉ ‘•‡‡‹ˆ‘”ƒ–‹‘ƒ††ƒ–ƒƒ„‘—––Š‡†‹•’Žƒ›‡†‘„Œ‡…–ǡ’”‡••–Š‡
Ȉ ‘•Ž‡™–‘–Š‡‘„Œ‡…–†‹•’Žƒ›‡†ǡ’”‡••Ǥ
Ȉ ‘•‡‡–Š‡‡š––‘—”‘„Œ‡…–ǡ’”‡••–Š‡‡›Ǥ
Ȉ ‘•‡‡‹ˆ‘”ƒ–‹‘ƒ††ƒ–ƒƒ„‘—––Š‡†‹•’Žƒ›‡†‘„Œ‡…–ǡ
desired speed. The number will appear in the upper-right corner of
the LCD display to indicate that the rate has been changed.
The hand control has a “double button” feature that allows you to
instantly speed up the motors without having to choose a speed rate.
To use this feature, simply press the arrow button that corresponds to
the direction that you want to move the telescope. While holding that
button down, press the opposite directional button. This will increase the
slew rate to the maximum slew rate.
When pressing the Up and Down arrow buttons in the slower slew
eyepiece (i.e. pressing the Up arrow button will move the star up in the
may need to press the opposite directional button to make the telescope
move in the correct direction.
1 = .5x*
4 = 8x
7 = .5º / sec
2 = 1x (sidereal)*
5 = 16x
8 = 2º / sec
3 = 4x
6 = 64x
9 = 4º / sec
*Rate 1 and 2 are photographic guide rates and are meant to be used
when the telescope is set up on a wedge in equatorial mode. These
rates can be used while set up in altazimuth, however the actual
the user control over the telescope’s many advanced features. All of the
setup and utility features can be accessed by pressing the MENU key and
scrolling through the options:
Tracking Mode – This allows you to change the way the telescope tracks
depending on the type of mount being used to support the telescope.
Ȉ ‘•Ž‡™–‘–Š‡‘„Œ‡…–†‹•’Žƒ›‡†ǡ’”‡••Ǥ
Ȉ ‘•‡‡–Š‡‡š––‘—”‘„Œ‡…–ǡ’”‡••–Š‡‡›Ǥ
The CPC has four direction buttons (3) in the center of the hand control
which control the telescope’s motion in altitude (up and down) and
speed rates.
This is the default tracking rate and is used
or tripod without the use of an equatorial
wedge. The telescope must be aligned with
two stars before it can track in altazimuth
Used to track the sky when the telescope
is polar aligned using an equatorial wedge in
the Northern Hemisphere.
Used to track the sky when the telescope
is polar aligned using an equatorial wedge in
the Southern Hemisphere.
When using the telescope for terrestrial
(land) observation, the tracking can be
Pressing the RATE key (11) allows you to instantly change the speed
rate of the motors from high speed slew rate to precise guiding rate or
anywhere in between. Each rate corresponds to a number on the hand
controller key pad. The number 9 is the fastest rate (3º per second,
and locating alignment stars. The number 1 on the hand control is the
slowest rate (.5x sidereal) and can be used for accurate centering of
rate of the motors:
Ȉ ”‡••–Š‡‡›‘–Š‡Šƒ†…‘–”‘ŽǤŠ‡™‹ŽŽ†‹•’Žƒ›–Š‡
current speed rate.
Ȉ ”‡••–Š‡—„‡”‘–Š‡Šƒ†…‘–”‘Ž–Šƒ–…‘””‡•’‘†•–‘–Š‡
>> www.celestron.com
Tracking Rate –ƒ††‹–‹‘–‘„‡‹‰ƒ„Ž‡–‘‘˜‡–Š‡–‡Ž‡•…‘’‡™‹–Š–Š‡
moves across the night sky. The tracking rate can be changed depending
This rate compensates for the rotation of
the Earth by moving the telescope at the same
rate as the rotation of the Earth, but in the
opposite direction. When the telescope is polar
aligned, this can be accomplished by moving
the telescope in right ascension only. When
mounted in Alt-Az mode, the telescope must
make corrections in both R.A. and declination.
Used for tracking the Moon when observing the
lunar landscape.
Used for tracking the Sun when solar observing.
View Time-Site – Displays the current time and longitude/latitude
time-site information like time zone, daylight saving and local sidereal
time. Local sidereal time (LST) is useful for knowing the right ascension
Time-Site will always display the last saved time and location entered
the hand control will only display the last saved time and location.
included in the regular database. There are several ways to save an
Save Sky Object – Š‡•–‘”‡•…‡Ž‡•–‹ƒŽ‘„Œ‡…–•–‘‹–•†ƒ–ƒ„ƒ•‡
by saving its right ascension and declination in the sky. This way the
Sky Obj” command and press ENTER. The display will ask you to
Save Land Object – The CPC can also be used as a spotting scope on
altitude and azimuth relative to the location of the telescope at the
the telescope, they are only valid for that exact location. To save land
down to the “Save Land Obj” command and press ENTER. The
display will ask you to enter a number between 1-200 to identify the
Save Database (Db) Object – This feature allows you to create your
Enter R.A. - Dec –‘—…ƒƒŽ•‘•–‘”‡ƒ•’‡…‹Ƥ…•‡–‘ˆ…‘‘”†‹ƒ–‡•ˆ‘”
Scroll to the “Enter RA-DEC” command and press ENTER. The display
database, scroll down to either GoTo Sky Obj or GoTo Land Obj and
The CPC will automatically retrieve and display the coordinates before
Get RA/DEC – Displays the right ascension and declination for the
current position of the telescope.
GoTo R.A/ Dec –ŽŽ‘™•›‘—–‘‹’—–ƒ•’‡…‹Ƥ…ǤǤƒ††‡…Ž‹ƒ–‹‘ƒ†
slew to it.
Identify Mode will search any of the CPC database catalogs or lists and
Identify Mode…ƒ„‡—•‡†–‘Ƥ†‘–Š‡”…‡Ž‡•–‹ƒŽ‘„Œ‡…–•–Šƒ–ƒ”‡…Ž‘•‡–‘
pointed at the brightest star in the constellation Lyra, choosing Identify
and then searching the Named Star catalog will no doubt return the star
Vega as the star you are observing. However, by selecting Identify and
searching by the Named Object or Messier catalogs, the hand control
your current position. Searching the Double Star catalog will reveal that
’•‹Ž‘›”ƒ‡‹•‘Ž›͙냙ƒ›ˆ”‘‡‰ƒǤ‘—•‡–Š‡ Identify feature:
Ȉ ”‡••–Š‡„—––‘ƒ†•‡Ž‡…––Š‡†‡–‹ˆ›‘’–‹‘Ǥ
Ȉ •‡–Š‡Ȁ•…”‘ŽŽ‡›•–‘•‡Ž‡…––Š‡…ƒ–ƒŽ‘‰–Šƒ–›‘—™‘—Ž†
like to search.
Ȉ ”‡••–‘„‡‰‹–Š‡•‡ƒ”…ŠǤ
Note: Some of the databases contain thousands of objects, and
can therefore take a minute or two to return the closest object.
Precise GoTo
view for astrophotography and CCD imaging. Precise GoTo automatically
the user to carefully center it in the eyepiece. The hand control then
1. Press the MENU button and use the Ȁ keys to select
Precise GoTo.
2. Choose Database–‘•‡Ž‡…––Š‡‘„Œ‡…––Šƒ–›‘—™ƒ––‘‘„•‡”˜‡ˆ”‘
any of the database catalogs listed
3. Choose RA/DEC to enter a set of celestial coordinates that you wish
to slew to.
͜Ǥ …‡–Š‡†‡•‹”‡†‘„Œ‡…–‹••‡Ž‡…–‡†ǡ–Š‡Šƒ†…‘–”‘Ž™‹ŽŽ•‡ƒ”…Š‘—–
to slew to the bright alignment star.
5. Use the direction buttons to carefully center the alignment star
in the eyepiece.
To store a set of coordinates (R.A./Dec) permanently into the CPC
database, save it as a •‡”‡Ƥ‡†„Œ‡…– as described above.
GoTo Object –‘‰‘–‘ƒ›‘ˆ–Š‡—•‡”†‡Ƥ‡†‘„Œ‡…–••–‘”‡†‹–Š‡
>> www.celestron.com
Setup Time-Site – Allows the user to customize the CPC display by
changing time and location parameters (such as time zone and
daylight savings).
Anti-backlash – All mechanical gears have a certain amount of backlash
or play between the gears. This play is evident by how long it takes for a
star to move in the eyepiece when the hand control arrow buttons are
pressed (especially when changing directions). The CPC’s anti-backlash
feature allows the user to compensate for backlash by inputting a value
between gears. The amount of compensation needed depends on the
for the star to appear to move in the eyepiece. There are two values for
each axis, positive and negative. Positive is the amount of compensation
applied when you press the button, in order to get the gears moving
quickly without a long pause. Negative is the amount of compensation
applied when you release the button, winding the motors back in the
other direction to resume tracking. You will need to experiment with
for most visual observing, whereas a higher value may be necessary
for photographic guiding. Positive backlash compensation is applied
when the mount changes its direction of movement from backwards to
forwards. Similarly, negative backlash compensation is applied when the
mount changes its direction of movement from forwards to backwards.
When tracking is enabled, the mount will be moving in one or both axes
in either the positive or negative direction, so backlash compensation will
always be applied when a direction button is released and the direction
moved is opposite to the direction of travel.
To set the anti-backlash value, scroll down to the anti-backlash option
responsiveness of each of the four arrow buttons. Note which directions
you see a pause in the star movement after the button has been pressed.
when pressing or releasing the button. Now, enter the same values
releasing the button, but setting the values lower results in a pause when
pressing the button, go with the higher value for positive, but use a lower
value for negative. CPC will remember these values and use them each
time it is turned on until they are changed.
Slew Limits – Sets the limits in altitude that the telescope can slew
without displaying a warning message. By default the slew limits are set
the horizon. However, the slew limits can be customized depending on
attached to your telescope preventing it from pointing straight-up,
you can set the maximum altitude limit to read 80º, thus preventing
altitude without warning.
Slew limits are applied relative to the base of the mount not the
actual horizon. So when setting the slew limits when using the
telescope on an equatorial wedge, remember that a minimum
slew limit of 0° would prevent the telescope from slewing down
past the celestial equator not the horizon. To set the slew limit so
that the telescope will slew to the horizon while on a wedge, you
must set the minimum slew limit to equal your latitude minus 90°.
Filter Limits – When an alignment is complete, the CPC automatically
>> www.celestron.com
scrolling through the database lists (or selecting the Tour function),
be above the horizon when you are observing. You can customize the
mountainous location where the horizon is partially obscured, you can
numeric keypad, the hand control will display a warning message before
If you want to explore the entire object database, set the
maximum altitude limit to 90º and the minimum limit to –90º.
This will display every object in the database lists regardless of
whether it is visible in the sky from your location.
Direction Buttons – The direction a star moves in the eyepiece varies
depending on the accessories being used. This can create confusion when
scope. To compensate for this, the direction of the drive control keys can
be changed. To reverse the button logic of the hand control, press the
MENU button and select Direction Buttons from the Utilities menu. Use
or altitude (up and down) button direction and press ENTER. Pressing
ENTER again will reverse the direction of the hand control buttons from
their current state. Direction Buttons will only change the eyepiece rates
GoTo Approach –Ž‡–•–Š‡—•‡”†‡Ƥ‡–Š‡†‹”‡…–‹‘–Šƒ––Š‡–‡Ž‡•…‘’‡™‹ŽŽ
heavy from using heavy optical or photographic accessories attached to
the back, you would want to set your altitude approach to the negative
direction. This would ensure that the telescope always approaches an
Similarly, if using the CPC polar aligned on a wedge, you would want
to set the azimuth approach to the direction that allows the scope to
To change the GoTo approach direction, simply choose GoTo Approach
from the Scope Setup menu, select either Altitude or Azimuth approach,
choose positive or negative and press ENTER.
Autoguide Rate – Allows the user to set an autoguide rate as a
percentage of sidereal rate. This is helpful when calibrating your
telescope to a CCD autoguider for long exposure photography.
Cordwrap – Cord wrap safeguards against the telescope slewing more
the telescope. This is useful when autoguiding or any time that cables are
plugged into the base of the telescope. By default, the cord wrap feature
when aligned on a wedge.
Custom Rate 9 – Allows the user to set the maximum slew speed when
provides more controlled slews when equipped with delicate imaging
and Dec axes. Enabling and disabling this feature will allow you to toggle
back and forth between the custom setting and the default setting.
numbers are for azimuth and the second set are for altitude.
Get Axis Position – Displays the relative altitude and azimuth for the
current position of the telescope.
GoTo Axis Position –ŽŽ‘™•›‘—–‘‡–‡”ƒ•’‡…‹Ƥ…ƒŽ–‹–—†‡ƒ†ƒœ‹—–Š
position and slew to it.
Hibernate – Hibernate allows the CPC to be completely powered down
and still retain its alignment when turned back on. This not only saves
power, but is ideal for those that have their telescopes permanently
mounted or leave their telescope in one location for long periods of time.
To place your telescope in Hibernate mode:
1. Select Hibernate from the Utility Menu.
2. Move the telescope to a desired position and press ENTER.
͛Ǥ ‘™‡”‘ơ–Š‡–‡Ž‡•…‘’‡Ǥ‡‡„‡”–‘‡˜‡”‘˜‡›‘—”
telescope manually while in Hibernate mode.
After pressing ENTER, you have the option of scrolling through the time/
the telescope.
Pressing UNDO at the Wake Up screen allows you to explore many
of the features of the hand control without waking the telescope
up from Hibernate mode. To wake up the telescope after UNDO
has been pressed, select Hibernate from the Utility menu and press
ENTER. Do not use the direction buttons to move the telescope
while in Hibernate mode.
Sun Menu
—Ž‡••‹–‹•Ƥ”•–‡ƒ„Ž‡†Ǥ‘‡ƒ„Ž‡–Š‡—ǡ‰‘–‘–Š‡Sun Menu and press
ENTER. The Sun will now be displayed in the Planets catalog and can
method. To remove the Sun from displaying on the hand control, once
again select the Sun Menu from the Utilities Menu and press ENTER.
Scrolling Menu
This menu allows you to change the rate of speed that the text scrolls
across the hand control display.
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Scrolling through the MENU (9) options will also provide access to
Correction, Hibernate, as well as many others.
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of the text.
telescope, the CPC still receives information, such as current time, from
Lights Control –Š‹•ˆ‡ƒ–—”‡ƒŽŽ‘™•›‘—–‘–—”‘ơ„‘–Š–Š‡”‡†‡›’ƒ†
light and LCD display for daytime use to conserve power and to help
preserve your night vision.
Factory Setting – Returns the CPC hand control to its original factory
setting. Parameters such as backlash compensation values, initial date
The hand control will ask you to press the “0” key before returning to the
factory default setting.
Version – Selecting this option will allow you to see the current version
Calibrate GoTo – GoTo Calibration is a useful tool when attaching heavy
visual or photographic accessories to the telescope. GoTo Calibration
calculates the amount of distance and time it takes for the mount to
balance of the telescope can prolong the time it takes to complete the
Set Mount Position
The Set Mount Position menu can be used to maintain your alignment
in cases where you wish to disengage the clutches or similar situations.
mount after having completed an alignment. To set the mount position
simply slew to a bright star in the named star list then select Set Mount
Position. The hand control will sync on the star by asking you to center
the star in the eyepiece and pressing the Align„—––‘Ǥ…‡•›…‡†‘
the star, you are free to manually move the mount in both axes in order
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and improving the tracking accuracy of the drive. This feature is for
advanced astrophotography and is used when your telescope is polar
using PEC, see the section on “Celestial Photography”.
to rebalance. When you are ready to slew the telescope to your next
star and carefully center it in the eyepiece. Using this tool will invalidate
the PEC index
Periodic Error Correction (PEC) – PEC is designed to improve
photographic quality by reducing the amplitude of the worm gear errors
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A telescope is an instrument that collects and focuses light. The nature of
the optical design determines how the light is focused. Some telescopes,
use mirrors. The EdgeHD optical system (Aplanatic Schmidt) uses a
combination of mirrors and lenses and is referred to as a compound or
while maintaining very short tube lengths, making them extremely
portable. The EdgeHD system consists of a zero power corrector plate, a
optical system, they travel the length of the optical tube three times.
enhanced multi-layer coatings on the primary and secondary mirrors
light from passing through to the eyepiece or camera.
The image orientation changes depending on how the eyepiece is
inserted into the telescope. When using the star diagonal, the image is
right-side-up, but reversed from left-to-right (i.e., mirror image).
star diagonal), the image is upside-down and reversed from left-to-right
(i.e., inverted). This is normal for the Schmidt-Cassegrain design.
The CPC’s focusing mechanism controls the primary mirror which is
The focusing knob, which moves the primary mirror, is on the rear cell
reached the end of its travel on the focusing mechanism. Turn the knob in
primary mirror only slightly. Therefore, it will take many turns (about 30)
you can go right through focus without seeing the image. To avoid this
Moon or a planet) so that the image is visible even when out of focus.
Critical focusing is best accomplished when the focusing knob is turned
visually and photographically, this is done by turning the focus knob
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help support and minimize lateral movement of the primary mirror
during astrophotography.
To use the mirror clutches:
͙Ǥ •‡–Š‡ˆ‘…—•‘„–‘ƒ†Œ—•––Š‡’”‹ƒ”›‹””‘”–‘–Š‡†‡•‹”‡†ˆ‘…—•Ǥ
͚Ǥ …‡‹ˆ‘…—•ǡ–—”–Š‡–™‘‹””‘”Ž‘…‘„•…Ž‘…™‹•‡—–‹Ž„‘–Šƒ”‡
very tight and can be turned no further.
Warning! Once the mirror is locked down, do not turn the focuser
the focus knob should not damage the telescope, undue stress can
be placed on the focus mechanisms causing excessive image shift
while focusing.
simply divide the focal length of the telescope by the focal length of the
Let’s say, for example, you are using the 40 mm Plössl eyepiece. To
telescope (the CPC 800, for example, has a focal length of 2032 mm) by
the focal length of the eyepiece, 40 mm. Dividing 2032 by 40 yields a
Although the power is variable, each instrument under average skies
formula looks like this:
almost a full degree.
To convert degrees to feet at 1,000 yards, which is more useful for
terrestrial observing, simply multiply by 52.5. Continuing with our
When working with any optical instrument, there are a few things to
remember to ensure you get the best possible image.
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is optically imperfect, and as a result, may vary in thickness from one
achieve a truly sharp image, while in some cases, you may actually see
a double image.
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includes asphalt parking lots on hot summer days or building rooftops.
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viewing terrestrially. The amount of detail seen under these conditions
is greatly reduced. Also, when photographing under these conditions,
lower contrast and underexposed.
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to remove them when observing with an eyepiece attached to the
telescope. When using a camera, however, you should always wear
stigmatism, corrective lenses must be worn at all times.
Up to this point, this manual covered the assembly and basic operation
of your CPC telescope. However, to understand your telescope more
thoroughly, you need to know a little about the night sky. This section
deals with observational astronomy in general and includes information
on the night sky and polar alignment.
constellation of Pisces designated as 0 hours, 0 minutes, 0 seconds. All
other points are designated by how far (i.e., how long) they lag behind this
coordinate after it passes overhead moving toward the west.
the northern celestial hemisphere from the southern. Like the Earth’s
latitude. However, in the sky this is referred to as declination, or DEC for
short. Lines of declination are named for their angular distance above
and below the celestial equator. The lines are broken down into degrees,
minutes of arc and seconds of arc. Declination readings south of the
equator carry a minus sign (-) in front of the coordinate and those north
of the celestial equator are either blank (i.e., no designation) or preceded
system that is similar to our geographical coordinate system here on
Earth. The celestial coordinate system has poles, lines of longitude and
background stars.
The celestial equivalent of longitude is called Right Ascension, or R.A. for
short. Like the Earth’s lines of longitude, they run from pole to pole and are
evenly spaced 15 degrees apart. Although the longitude lines are separated
by an angular distance, they are also a measure of time. Each line of
longitude is one hour apart from the next. Since the Earth rotates once
every 24 hours, there are 24 lines total. As a result, the R.A. coordinates
The daily motion of the Sun across the sky is familiar to even the
most casual observer. This daily trek is not the Sun moving as early
astronomers thought, but the result of the Earth’s rotation. The Earth’s
rotation also causes the stars to do the same, scribing out a large circle
as the Earth completes one rotation. The size of the circular path a star
follows depends on where it is in the sky. Stars near the celestial equator
form the largest circles rising in the east and setting in the west. Moving
toward the north celestial pole, the point around which the stars in the
northern hemisphere appear to rotate, these circles become smaller.
Stars in the mid-celestial latitudes rise in the northeast and set in the
northwest. Stars at high celestial latitudes are always above the horizon,
and are said to be circumpolar because they never rise and never set. You
will never see the stars complete one circle because the sunlight during
the day washes out the starlight. However, part of this circular motion
of stars in this region of the sky can be seen by setting up a camera on
will reveal semicircles that revolve around the pole. (This description of
stellar motions also applies to the southern hemisphere except all stars
south of the celestial equator move around the south celestial pole.)
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Alt-Az position, it is still necessary to align the polar axis of the telescope
(the fork arm) to the Earth’s axis of rotation in order to do long exposure
astrophotography. To do an accurate polar alignment, the CPC requires
an optional equatorial wedge between the telescope and the tripod. This
allows the telescope’s tracking motors to rotate the telescope around the
celestial pole, the same way as the stars. Without the equatorial wedge,
you would notice the stars in the eyepiece would slowly rotate around
unnoticed when viewing with an eyepiece, it would be very noticeable
when imaging.
Polar alignment is the process by which the telescope’s axis of rotation
(called the polar axis) is aligned (made parallel) with the Earth’s axis of
The CPC hand control has a polar alignment function called “All-Star”
polar alignment that will help you polar align your telescope for increased
tracking precision and astrophotography. This feature allows you to choose
any bright alignment stars to assist in accurately aligning your telescope and
wedge with the North Celestial Pole. Before using the Polar Align feature,
Updating your Star Alignment
After polar alignment, it’s a good idea to check the pointing accuracy
the mount. Since the polar alignment process requires you to “sync” the
telescope on a bright star before you begin, it will be necessary to undo
the sync before re-aligning. To undo the sync:
1. Press the Align„—––‘ƒ†—•‡–Š‡Ȁ„—––‘•‘–Š‡Šƒ†
controller to select Undo Sync from the list, and press Enter. The
message Complete will display on the LCD.
in its Named Star database list. This will be the star used for the All-Star
alignment star that is high in the sky and near the Meridian. Try to avoid
stars that are close to the west/east horizon, directly overhead or too
near the celestial pole.
To re-align your telescope:
Press the Align button and use the Up/Down buttons on the hand
controller to select Polar Align from the list.
3. The hand control will ask you which of the original alignment stars
›‘—™‹•Š–‘”‡’Žƒ…‡Ǥ•‡–Š‡Ȁ„—––‘•–‘•‡Ž‡…––Š‡ desired star and press Enter.
The Polar Align feature has two options: Align Wedge and Display Align.
Align Wedge Ȃˆ–‡”’‡”ˆ‘”‹‰ƒ‘”–Š‘”‘—–ŠŽ‹‰‡–ƒ†
slewing your telescope to any bright star in the telescope’s database,
select the “Align Wedge” option. The telescope will then re-slew to the
same star.
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2. Then accurately center the star in your eyepiece and press
the position that the star should be if it were accurately
polar aligned.
Optional Accessories) or a high power eyepiece to precisely center the
2. Slew the telescope to one of the original alignment stars, or another
bright star if the original alignment stars are no longer in a
convenient location. Press the Align„—––‘ƒ†—•‡–Š‡Ȁ
buttons on the hand controller to select Alignment Stars from
the list.
5. Then center the star in the eyepiece and Press Align.
Display Align – the user can now display the polar alignment error
in the RA and DEC axes. These values show how close the mount
is pointed at the celestial pole based on how accurately the user
centered the alignment star with the hand control and with the mount
1. Press the Align„—––‘ƒ†—•‡–Š‡Ȁ„—––‘•‘–Š‡Šƒ†
controller to select Display Align from the list, and press Enter.
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star in the center of the eyepiece. ‘‘–—•‡–Š‡†‹”‡…–‹‘
now be pointed towards the North Celestial Pole.
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other stars appear to rotate. These points are called the celestial poles
in the northern hemisphere all stars move around the north celestial
pole. When the telescope’s polar axis is pointed at the celestial pole, it
is parallel to the Earth’s rotational axis.
(North Star)
the south celestial pole are not nearly as bright as those around the
minutes from the pole.
The north celestial pole is the point in the northern hemisphere
around which all stars appear to rotate. The counterpart in the
southern hemisphere is referred to as the south celestial pole.
Declination Drift Method of Polar Alignment
This method of polar alignment allows you to get the most accurate
alignment on the celestial pole and is required if you want to do long
exposure deep-sky astrophotography through the telescope. The
declination drift method requires that you monitor the drift of selected
stars. The drift of each star tells you how far away the polar axis is
pointing from the true celestial pole and in what direction. Although
declination drift is simple and straight-forward, it requires a great deal
drift method should be done after any one of the previously mentioned
methods has been completed.
star, Polaris, is the end star in the handle of the Little Dipper. Since the
Little Dipper (technically called Ursa Minor) is not one of the brightest
(the pointer stars). Draw an imaginary line through them toward the
Big Dipper changes during the year and throughout the course of the
not as fortunate as those in the northern hemisphere. The stars around
To perform the declination drift method you need to choose two
south near the meridian. Both stars should be near the celestial
one at a time and in declination only. While monitoring a star on the
meridian, any misalignment in the east-west direction is revealed.
While monitoring a star near the east/west horizon, any misalignment
close alignment, a Barlow lens is also recommended since it increases
hair eyepiece and align the cross hairs so that one is parallel to the
declination axis and the other is parallel to the right ascension axis.
Move your telescope manually in R.A. and DEC to check parallelism.
meet. The star should be approximately within 1/2 an hour of the
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Ȉ ˆ–Š‡•–ƒ”†”‹ˆ–•‘”–Šǡ–Š‡’‘Žƒ”ƒš‹•‹•–‘‘ˆƒ”™‡•–Ǥ
Big Dipper
eastern horizon. The star should be 20 degrees above the horizon and
Little Dipper
(North Star)
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Ȉ ˆ–Š‡•–ƒ”†”‹ˆ–•‘”–Šǡ–Š‡’‘Žƒ”ƒš‹•‹•–‘‘Š‹‰ŠǤ
eliminated, the telescope is very accurately aligned. You can now do
prime focus deep-sky astrophotography for long periods.
NOTE: If the eastern horizon is blocked, you may choose a star near
the western horizon, but you must reverse the polar high/low error
directions. Also, if using this method in the southern hemisphere,
the direction of drift is reversed for both R.A. and DEC.
>> www.celestron.com
With your telescope set up, you are ready to use it for observing. This
section covers visual observing hints for both solar system and deep
your ability to observe.
face we see is fully illuminated and its light can be overpowering.
amount of detail on the lunar surface. At low power you will be able to
see most of the lunar disk at one time. The optional Reducer/Corrector
lens allows for breath-taking views of the entire lunar disk when used
focus in on a smaller area. Choose the lunar tracking rate from the CPC’s
MENU tracking rate options to keep the Moon centered in the eyepiece
Lunar Observing Hints
Venus go through its lunar-like phases. Mars can reveal a host of surface
detail and one, if not both, of its polar caps. You will be able to see the
cloud belts of Jupiter and the Great Red Spot (if it is visible at the time
Jupiter as they orbit the giant planet. Saturn, with its beautiful rings, is
easily visible at moderate power.
Planetary Observing Hints
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factor on how much planetary detail will be visible. So, avoid
observing the planets when they are low on the horizon or when
they are directly over a source of radiating heat, such as a rooftop
or chimney. See “Seeing Conditions” later in this section.
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Although overlooked by many amateur astronomers, solar observation
is both rewarding and fun. However, because the Sun is so bright, special
precautions must be taken when observing our star so as not to damage
your eyes or your telescope.
the folded optical design, tremendous heat build-up will result inside
the optical tube. This can damage the telescope and/or any accessories
attached to the telescope.
they move across the solar disk and faculae, which are bright patches
seen near the Sun’s edge.
Solar Observing Hints
Ȉ Š‡„‡•––‹‡–‘‘„•‡”˜‡–Š‡—‹•‹–Š‡‡ƒ”Ž›‘”‹‰‘”Žƒ–‡ afternoon when the air is cooler.
Ȉ ‘…‡–‡”–Š‡—™‹–Š‘—–Ž‘‘‹‰‹–‘–Š‡‡›‡’‹‡…‡ǡ™ƒ–…Š–Š‡ shadow of the telescope tube until it forms a circular shadow.
Ȉ ‘‡•—”‡ƒ……—”ƒ–‡–”ƒ…‹‰ǡ„‡•—”‡–‘•‡Ž‡…––Š‡•‘Žƒ”–”ƒ…‹‰”ƒ–‡Ǥ
>> www.celestron.com
nebulae, double stars and other galaxies outside our own Milky Way.
moderate power is all you need to see them. Visually, they are too faint
they appear black and white. And, because of their low surface brightness,
they should be observed from a dark-sky location. Light pollution around
background sky brightness, thus increasing contrast.
an observing session. Conditions include transparency, sky illumination
observing will help you get the most out of your telescope.
clouds, moisture and other airborne particles. Thick cumulus clouds are
completely opaque while cirrus can be thin, allowing the light from the
brightest stars through. Hazy skies absorb more light than clear skies
is inky black.
General sky brightening caused by the Moon, aurorae, natural airglow and
brighter stars and planets, bright skies reduce the contrast of extended
observing, limit deep sky viewing to moonless nights far from the light
sky viewing from light polluted areas by blocking unwanted light while
hand, observe planets and stars from light polluted areas or when the
Moon is out.
Seeing conditions refers to the stability of the atmosphere and directly
atmosphere acts as a lens which bends and distorts incoming light rays.
The amount of bending depends on air density. Varying temperature
imperfect or smeared image. These atmospheric disturbances vary from
time-to-time and place-to-place. The size of the air parcels compared
to your aperture determines the “seeing” quality. Under good seeing
Mars, and stars are pinpoint images. Under poor seeing conditions,
images are blurred and stars appear as blobs.
The conditions described here apply to both visual and photographic
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After looking at the night sky for a while, you may want to try
photographing it. Several forms of celestial photography are possible
with your telescope, including short exposure prime focus, eyepiece
Each of these is discussed in moderate detail with enough information to
get you started. Topics include the accessories required and some simple
techniques. More information is available in some of the publications
listed at the end of this manual.
focus capability or mirror lock up. Here are the mandatory features a
which allows for time exposures. This excludes point and shoot cameras
and limits the selection to SLR cameras, the most common type of
35 mm camera on the market today.
Short exposure prime focus photography is the best way to begin
telescope without an eyepiece or camera lens in place. To attach your
The T-Ring replaces the 35 mm SLR camera’s normal lens. Prime focus
To attach your camera to your telescope:
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also remove the 3” adapter plate threaded onto the rear of the tube)
new electronic cameras use the battery to keep the shutter open during
or not. Look for a camera that has a manual shutter when operating in
others have made such camera bodies.
The camera must have interchangeable lenses so you can attach it to the
not 100% functional. The light meter, for example, does not have to be
operational since you will be determining the exposure length manually.
You will also need a cable release with a locking function to hold the
shutter open. Mechanical and air release models are available.
Lunar Phase
ISO 50
ISO 100
ISO 200
ISO 400
2. Thread the T-Ring onto the T-Adapter.
3. Mount your camera body onto the T-Ring the same as you would for
a standard camera lens.
4. Thread the T-Adapter onto the back of the telescope while holding
the camera in the desired orientation (either vertical or horizontal).
With your camera attached to the telescope, you are ready for prime
to do it:
͙Ǥ ‡–‡”–Š‡‘‘‹–Š‡Ƥ‡Ž†‘ˆ›‘—”–‡Ž‡•…‘’‡Ǥ
͚Ǥ ‘…—•–Š‡–‡Ž‡•…‘’‡„›–—”‹‰–Š‡ˆ‘…—•‘„—–‹Ž–Š‡‹ƒ‰‡‹•
sharp. Make sure the mirror lock knobs are loosened.
͛Ǥ ‡––Š‡•Š—––‡”•’‡‡†–‘–Š‡ƒ’’”‘’”‹ƒ–‡•‡––‹‰ȋ•‡‡‹‰—”‡͠Ǧ͙ȌǤ
4. Trip the shutter using a cable release or self timer.
5. Use your camera’s bracketing feature to automatically change
The exposure times listed in table 8-1 should be used as a starting
point. Always make exposures that are longer and shorter than the
recommended time. Also, take a few photos at each shutter speed.
This will ensure that you will get a good photo.
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>> www.celestron.com
angular sizes, primarily the Moon and planets. Planets, although
physically quite large, appear small in angular size because of their
to make the image large enough to see any detail. Unfortunately,
the camera/telescope combination alone does not provide enough
image large enough, you must attach your camera to the telescope with
T-ring for your particular camera make (i.e., Minolta, Nikon, Pentax, etc.).
to take photos of varying duration and keep accurate records of what you
have done. Record the date, telescope, exposure duration, eyepiece,
eyepiece. All exposure times are listed in seconds or fractions of
a second.
ISO 50
ISO 100
ISO 200
ISO 400
35 mm SLR
Visual Back
vibration to smear the image. To get around this, use the camera’s self–‹‡”‹ˆ–Š‡‡š’‘•—”‡–‹‡‹•Ž‡••–Šƒ‘‡•‡…‘†Ȃƒ…‘‘‘……—””‡…‡
“hat trick.” This technique incorporates a hand-held black card placed
over the aperture of the telescope to act as a shutter. The card prevents
the shutter has been released and the vibration has diminished (a few
the exposure is complete, place the card over the front of the telescope
Here’s the process for making the exposure.
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2. Turn the focus knob until the image is as sharp as possible.
3. Place the black card over the front of the telescope.
4. Release the shutter using a cable release.
5. Wait for the vibration caused by releasing the shutter to diminish.
Also, wait for a moment of good seeing.
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of the exposure (see accompanying table).
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8. Close the camera’s shutter.
The exposure times listed here should be used as a starting point. Always
make exposures that are longer and shorter than the recommended
time. Also, take a few photos at each shutter speed. This will ensure that
NOTE: Don’t expect to record more detail than you can see
visually in the eyepiece at the time you are photographing.
This is the last form of celestial photography to be attempted after
There are several techniques for this type of photography, and the
one chosen will determine the standard accessories needed. The best
guider. This device allows you to photograph and guide through the
need a T-Ring to attach your camera to the Radial Guider.
forms of astrophotography which allows for fairly loose guiding, prime
focus requires meticulous guiding for long periods. To accomplish this
you need a guiding ocular with an illuminated reticle to monitor your
1. Polar align the telescope using an optional equatorial wedge. To polar
see the Polar Alignment section earlier in the manual.
2. Remove all visual accessories.
3. Thread the Radial Guider onto your telescope.
4. Thread the T-Ring onto the Radial Guider.
>> www.celestron.com
5. Mount your camera body onto the T-Ring the same as you would any
other lens.
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͟Ǥ ‘…—•–Š‡–‡Ž‡•…‘’‡‘ƒ•–ƒ”Ǥ
͠Ǥ ‡–‡”›‘—”•—„Œ‡…–‹–Š‡Ƥ‡Ž†‘ˆ›‘—”…ƒ‡”ƒǤ
͡Ǥ ‹†ƒ•—‹–ƒ„Ž‡‰—‹†‡•–ƒ”‹–Š‡–‡Ž‡•…‘’‡Ƥ‡Ž†ǤŠ‹•…ƒ„‡–Š‡‘•–
time consuming process.
11. Monitor your guide star for the duration of the exposure using the
buttons on the hand controller to make the needed corrections.
12.Close the camera’s shutter.
PEC for short, is a system that improves the tracking accuracy of the
drive by reducing the number of user corrections needed to keep a guide
star centered in the eyepiece. PEC is designed to improve photographic
quality by reducing the amplitude of the worm errors. Using the PEC
position of its worm gear so that it has a reference when playing back
the recorded error. Next, you must guide for at least 8 minutes during
worm gear 8 minutes to make one complete revolution, hence the need
to guide for 8 minutes). This “teaches” the PEC chip the characteristics
of the worm. The periodic error of the worm gear drive will be stored in
the PEC chip and used to correct periodic error. The last step is to play
this feature is for advanced astrophotography and still requires careful
guiding since all telescope drives have some periodic error.
eyepiece, it will have to be re-centered before the recording begins.
prepare for guiding, it is best to restart PEC recording after the worm
gear has found its index.
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͟Ǥ ‘‹––Š‡–‡Ž‡•…‘’‡ƒ––Š‡‘„Œ‡…–›‘—™ƒ––‘’Š‘–‘‰”ƒ’Šƒ†…‡–‡”
the guide star on the illuminated cross hairs and you are ready to play
back the periodic error correction.
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function to begin playing back the correction for future photographic
and repeat the recording processes again. The previously recorded
information will be replaced with the current information. Repeat
Does the PEC function make unguided astrophotography possible? Yes and
exposure, deep sky astrophotography. The optional Reducer/Corrector lens
reduces exposure times making the task of guiding a little easier.
shortest possible time. Here are proven recommendations:
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Ȉ ‘‹…ƒ͚͛͘͘ȋ…‘Ž‘”’”‹–Ȍ
Ȉ —Œ‹…Š”‘‡͙͘͘͞ȋ…‘Ž‘”•Ž‹†‡Ȍ
Ȉ ͙͛͘͘͘ȋ…‘Ž‘”•Ž‹†‡Ȍ
Ȉ …‘–…Š…Š”‘‡͘͘͜
Using Periodic Error Correction
Ȉ Ǧƒš͚͛͘͘ȋ„Žƒ…ƒ†™Š‹–‡’”‹–Ȍ
EQ South for southern hemisphere) method, select PEC from the Utilities
menu and press ENTER to begin recording your periodic error. Here’s
how to use the PEC function.
Ȉ Ǧƒš͘͘͜ȋ„Žƒ…ƒ†™Š‹–‡’”‹–Ȍ
͙Ǥ ‹†ƒ„”‹‰Š–•–ƒ””‡Žƒ–‹˜‡Ž›…Ž‘•‡–‘–Š‡‘„Œ‡…–›‘—™ƒ–
to photograph.
Ȉ –ƒ”͙͚͝ȋ…‘Ž‘”’”‹–Ȍ
͚Ǥ •‡”–ƒŠ‹‰Š’‘™‡”‡›‡’‹‡…‡™‹–Š‹ŽŽ—‹ƒ–‡†…”‘••Šƒ‹”•‹–‘›‘—”
parallel to the declination while the other is parallel to the R.A. axis.
Ȉ ‡…Šƒǡ‰ƒ•Š›’‡”‡†ȋ„Žƒ…ƒ†™Š‹–‡’”‹–Ȍ
3. Center the guide star on the illuminated cross hairs, focus the
telescope and study the periodic movement.
4. Before actually recording the periodic error, take a few minutes to
practice guiding. Set the hand control slew rate to an appropriate
guide rate (rate 1 = .5x, rate 2 = 1x) and practice centering the guide
star in the cross hairs for several minutes. This will help you familiarize
yourself with the periodic error of the drive and the operation of
the hand control. Remember to ignore declination drift when
programming the PEC.
Note: When recording PEC, only the photo guide rates (rates
1 and 2) will be operational. This eliminates the possibility of
moving the telescope suddenly while recording.
5. To begin recording the drive’s periodic error, press the MENU button
buttons to display the Record option and press ENTER. You will have
observing session that PEC record or play is selected, the worm gear
>> www.celestron.com
are designed or specially treated for celestial photography. Here are
some popular choices:
Ȉ —Œ‹…Š”‘‡͙͘͘ȋ…‘Ž‘”•Ž‹†‡Ȍ
Ȉ Ǧƒš͘͘͜ȋ„Žƒ…ƒ†™Š‹–‡’”‹–Ȍ
There is no exposure determination table to help you get started. The
best ways to determine exposure length is to look at previously published
unguided sample photos of various parts of the sky while the drive is
running. Always take exposures of various lengths to determine the best
exposure time.
Your CPC makes an excellent telephoto lens for terrestrial (land)
photography. Terrestrial photography is best done with the telescope in
metering which lets you know if your picture is under or overexposed.
metering and changing shutter speeds
Reducing Vibration
Releasing the shutter manually can cause vibrations, producing blurred
photos. To reduce vibration when tripping the shutter, use a cable
release. A cable release keeps your hands clear of the camera and lens,
thus eliminating the possibility of introducing vibration. Mechanical
shutter releases can be used, though air-type releases are best. Blurry
pictures can also result from shutter speeds that are too slow. To prevent
exposure length is virtually unlimited.
Fastar Option – Using your EdgeHD telescope at f/2 with optional
lens assembly.
The EdgeHD telescopes are equipped with a removable secondary
mirror that allows you to convert your f/10 telescope into an f/2 imaging
system capable of exposure times 25 times shorter than those needed
making it the most versatile imaging system available today. With an
telescope to f/2 prime focus use in a matter of seconds. This makes the
Another way to reduce vibration is with the Vibration Suppression Pads
(#93503). These pads rest between the ground and tripod feet. They
reduce the vibration amplitude and vibration time.
The following is a brief description of the advantages of imaging at each
telescope in any of its many settings
f/6.3 with Reducer/Corrector
Ring Nebula) and small galaxies (M104, the Sombrero Galaxy), larger
Medium size to small galaxies –ˆȀ͞Ǥ͛‹ƒ‰‹‰‰‹˜‡•›‘—Ƥ‡””‡•‘Ž—–‹‘
then at f/2, but the slower f-number will usually require you to guide
the image while you are taking longer exposures. Guiding can be
accomplished by using an optional Radial Guider or a piggyback guide
scope. The exposure times are about 10 times longer, but the results can
Galaxy) can be imaged under dark skies with a series of short exposures
using Track and Accumulate. Ten exposures at 15 seconds each will yield
a nice image and is short enough that you may not need to guide the
Lunar or small planetary nebulae – f/10 imaging is more challenging for
long exposure, deep-sky imaging. Guiding needs to be very accurate and
the exposure times need to be much longer, about 25 times longer than
should be shot at f/20. The Ring Nebula is a good candidate because it is
seconds at f/10. The longer the exposure, the better.
Planetary or Lunar – f/20 is a great way to image the planets and
features on the Moon. When imaging the planets, very short exposures
are needed. The exposure lengths range from .03 to .1 seconds on
Generally you will take one image after another until one looks good.
exposures you might save 1. To image at f/20, you need to purchase a 2x
Barlow and a T-adapter or Radial Guider.
using the optional CCD camera for f/2 imaging.
Warning: The secondary mirror should never be removed unless
can easily be made by turning the screws on the top of the secondary
mirror mount without ever having to remove the secondary mirror (see
Telescope Maintenance section of this manual).
The f/# stands for the ratio between the focal length and the diameter
tube has a focal length of 110 inches and a diameter of 11 inches. This
makes the system an f/10, (focal length divided by diameter). When
position, the system becomes f/2. This is a unique feature to some
>> www.celestron.com
view, image size and pixel resolution. As the f-number goes down (or
That makes the exposure time needed about 25 times shorter than at
80” (2032 mm)
93” (2350 mm)
110” (2800 mm)
F /2
16” (406.4 mm)
18.5” (470 mm)
23.1” (587 mm)
Auto Guiding
The CPC has a designated auto guiding port for use with a CCD
cable to the CPC and calibrating the autoguider. Note that the four
outputs are active-low with internal pull-ups and are capable of sinking
25 mA DC.
12 3456
1 = No Connect
2 = Ground
3 = +RA (Right)
4 = +DEC (Up)
5 = -DEC (Down)
6 = -RA (Left)
>> www.celestron.com
While your CPC telescope requires little maintenance, there are a few
things to remember that will ensure your telescope performs at its best.
of your telescope. Special care should be taken when cleaning any
instrument so as not to damage the optics.
of camel’s hair) or a can of pressurized air. Spray at an angle to the lens
for approximately two to four seconds. Then, use an optical cleaning
solution and white tissue paper to remove any remaining debris. Apply
the solution to the tissue and then apply the tissue paper to the lens.
Low pressure strokes should go from the center of the corrector to the
You can use a commercially made lens cleaner or mix your own. A good
cleaning solution is isopropyl alcohol mixed with distilled water. The
quart of water) can be used.
observing, the dew must be removed, either with a hair dryer (on low
setting) or by pointing the telescope at the ground until the dew
has evaporated.
accessories from the rear cell of the telescope. Place the telescope
in a dust-free environment and point it down. This will remove the
moisture from the telescope tube.
To minimize the need to clean your telescope, replace all lens covers
cover should be placed over the opening when not in use. This will
prevent contaminants from entering the optical tube.
call the factory for a return authorization number and price quote.
The optical performance of your CPC telescope is directly related to its
collimation, that is the alignment of its optical system. Your CPC was
collimated at the factory after it was completely assembled. However,
have to be collimated. The only optical element that may need to be
To verify collimation, view a star near the zenith. Use a medium to high
skewing of the star to one side, then re-collimation is needed.
To check the collimation of your telescope you will need a light source.
A bright star near the zenith is ideal since there is a minimal amount of
atmospheric distortion. Make sure that tracking is on so that you won’t
means that it moves very little thus eliminating the need to manually
track it.
Before you begin the collimation process, be sure that your telescope is
in thermal equilibrium with the surroundings. Allow 45 minutes for the
telescope to reach equilibrium if you move it between large
temperature extremes.
>> www.celestron.com
To accomplish this, you need to tighten the secondary collimation
skewed light. These screws are located on the secondary mirror holder
the collimation screw cover to expose the three collimation screws
moving the scope before making any improvements or before making
To make collimation a simple procedure, follow these easy steps:
1. While looking through a medium to high power eyepiece, de-focus a
9-2). Center the de-focused star and notice in which direction the
central shadow is skewed.
skewed, than you are turning the collimation screw the wrong way.
Turn the screw in the opposite direction, so that the star image is
͞Ǥ ˆ™Š‹Ž‡–—”‹‰›‘—‘–‹…‡–Šƒ––Š‡•…”‡™•‰‡–˜‡”›Ž‘‘•‡ǡ–Š‡•‹’Ž›
tighten the other two screws by the same amount. Conversely, if the
collimation screw gets too tight, then loosen the other two screws by
the same amount.
͟Ǥ …‡–Š‡•–ƒ”‹ƒ‰‡‹•‹–Š‡…‡–‡”‘ˆ–Š‡Ƥ‡Ž†‘ˆ˜‹‡™ǡ…Š‡…–‘•‡‡
the same direction, then continue turning the screw(s) in the same
the new direction.
͚Ǥ Žƒ…‡›‘—”Ƥ‰‡”ƒŽ‘‰–Š‡‡†‰‡‘ˆ–Š‡ˆ”‘–…‡ŽŽ‘ˆ–Š‡–‡Ž‡•…‘’‡
(be careful not to touch the corrector plate), pointing towards the
until its shadow is seen closest to the narrowest portion of the rings
(i.e., the same direction in which the central shadow is skewed).
͛Ǥ ‘…ƒ–‡–Š‡…‘ŽŽ‹ƒ–‹‘•…”‡™…Ž‘•‡•––‘™Š‡”‡›‘—”Ƥ‰‡”‹•
positioned. This will be the collimation screw you will need to
4. Use the hand control buttons to move the de-focused star image to
obstruction of the star image is skewed.
5. While looking through the eyepiece, use an Allen wrench to turn the
collimation screw you located in step 2 and 3. Usually a tenth of a turn
Wait until a better night if it is turbulent or aim to a steadier part of the
the accessories are listed in alphabetical order.
”‡…–ƒ‰‡‹ƒ‰‘ƒŽȋ͙͙͚͗͜͡ǦȌȂ This accessory is an Amici prism
with images that are oriented properly (upright and correct from
›‡’‹‡…‡•Ȃ Like telescopes, eyepieces come in a variety of designs.
ŽÚ••ŽȂ Plössl eyepieces have a 4-element lens designed for
low-to-high power observing. All are fully multi-coated for maximum
ǦȂ The newly enhanced X-Cel LX eyepiece series is what you’ve
been waiting for in a high quality eyepiece for planetary viewing. With
a brand new sleek and robust design and a twist-up eye guard, these
eyepieces are especially designed for comfort and ease of use. They also
>> www.celestron.com
parfocal and require little to no focusing when
changing from low to high power. The X-Cel LX
25 mm. Ž–‹ƒȂCelestron Ultima LX Series
twist-up eyecups - Good for eyeglass wearers.
22 mm and 32 mm.
—‹†‡ȋ͙͙͗͜͟͡ȌȂ This multipurpose 12.5 mm illuminated
reticle can be used for guiding deep-sky astrophotos, measuring position
angles, angular separations and more. The laser etched reticle provides
razor sharp lines, and the variable brightness illuminator is completely
cordless. The Micro Guide Eyepiece produces 224 power when used with
in lunar and planetary observing. They
reduce glare and light scattering,
increase contrast through selective
resolution, reduce irradiation and
lessen eye fatigue. Celestron’s
plane parallel glass with excellent
Neutral Density.
Žƒ•ŠŽ‹‰Š–ǡ‹‰Š–‹•‹‘ȋ͗͛͡͝͠͠ȌȂ Celestron’s premium model for
astronomy, using two red LEDs to preserve night vision better than red
9 volt battery (included).
This includes mercury and high and low pressure sodium vapor lights.
1.25” eyepieces (#94123) and 2” eyepieces (#94124).
rechargeable power supply. Comes with
two 12v output cigarette outlets, built-in
120v AC adapter and cigarette lighter
—‹†‡”ȋ͙͗͜͟͡͞ȌȂ The Celestron
Radial Guider®‹••’‡…‹Ƥ…ƒŽŽ›†‡•‹‰‡†
for use in prime focus, deep sky astrophotography and takes the place
of the T-Adapter. This device allows you to photograph and guide
simultaneously through the optical tube assembly of your telescope. This
type of guiding produces the best results since what you see through the
Guider is a “T”-shaped assembly that
attaches to the rear cell of the telescope.
As light from the telescope enters the
guider, most passes straight through to
the camera. A small portion, however, is
up to the guiding eyepiece. This guider has
housing rotate independently of the
camera orientation making the acquisition
of a guide star quite easy. Second, the
prism angle is tunable allowing you to look at guide stars on-axis. This
accessory works especially well with the Reducer/Corrector.
Ǧ†ƒ’–‡”Ȃ This T-Adapter allows you to
attach your 35 mm DSLR camera to the
prime focus of your EdgeHD telescope.
This arrangement is used for terrestrial
photography and short exposure lunar and
long exposure deep-sky photography when
CPC Deluxe 925 and 1100 HD.
Ǧ‹‰Ȃ The T-Ring couples your 35 mm SLR camera body to the
T-Adapter, radial guider, or tele-extender. This accessory is mandatory
if you want to do DSLR photography through the telescope. Celestron
provides a T-ring for both Nikon (#93402) and Canon (#93419).
‡Ž‡Ǧš–‡†‡”ǡ‡Ž—š‡ȋ͗͛͛͜͡͞ȌȂ The tele-extender is a hollow tube
that allows you to attach a camera to the telescope when the eyepiece
which allows you to capture very high power views of the Sun, Moon and
back. This tele-extender works with eyepieces that have large housings,
like the Celestron Ultima series.
”‘‡†‰‡ȋ͗͛͜͡͞͞ȌȂ Celestron’s HD Pro Wedge allows you
to tilt the telescope so that its polar axis is parallel to the earth’s
your CPC DeluxeHD for guided
astrophotography. The Pro Wedge is
designed to support our fork mounted
telescopes up to 11”. The HD Pro Wedge
provides a heavy duty, stable platform
that is perfect for astroimaging and
guarantees minimal vibration. A low
latitude range of 0-90 degrees makes
this wedge functional for use at
the equator.
A full description of all Celestron accessories can be found in the Celestron
Accessory Catalog (#93685).
>> www.celestron.com
Optical Specification
CPC Deluxe 800 HD – #11007
CPC Deluxe 925 HD – #11008
203 mm (8”) EdgeHD Optics
235 mm (9.25”) EdgeHD Optics
Focal Length
2032 mm
2350 mm
F/ratio of the Optical System
Primary Mirror:
Fine Annealed Pyrex
Starbright XLT Coating
Fine Annealed Pyrex
Starbright XLT Coating
Optical Quality Crown Glass
A-R Coatings both sides
Optical Quality Crown Glass
A-R Coatings both sides
Highest Useful Magnification
480x (~4 mm eyepiece)
555x (~4 mm eyepiece)
660x (~4 mm eyepiece)
Lowest Useful Magnification
(7 mm exit pupil)
29x (~70 mm eyepiece)
34x (~70 mm eyepiece)
40x (~70 mm eyepiece)
Magnification: Standard Eyepiece
.68 arc seconds
.57 arc seconds
.59 arc seconds
.49 arc seconds
Light Gathering Power
Near Focus with Standard Eyepiece
or Camera
~25 feet
~40 feet
Central Obstruction
Corrector Plate:
Rayleigh Criterion
Dawes Limit
CPC Deluxe 1100 HD – #11009
280 mm (11”) EdgeHD Optics
2800 mm
Fine Annealed Pyrex
Starbright XLT Coating
Optical Quality Crown Glass
A-R Coatings both sides
.50 arc seconds
.42 arc seconds
~100 feet
Field of View: Standard Eyepiece
Linear Field of View (at 1000 yds)
44 ft.
42 ft.
35 ft.
Optical Tube Length
Weight of Telescope
42 lbs
58 lbs
65 lbs
Weight of Tripod
19 lbs
19 lbs
19 lbs
nput Voltage
12 V DC Nominal
15 V DC Max
9 V DC Min
Power Supply Requirements
12 VDC-2.5A (Tip positive)
Internal 48 channel
Motor: Type
Slew speeds
DC Servo motors with encoders, both axes
.1406 arc sec
Nine slew speeds: 4º /sec, 2º /sec, .5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
Hand Control
Double line, 16 character Liquid Crystal Display
19 fiber optic backlit LED keypad
Fork Arm
Dual Fork tine cast aluminum with detachable HC holder
5.78”, precision brass gears on RA axes, 180 tooth.
Stainless steel worm gear
9.8” Azimuth Bearing Surface
Optical Tube
>> www.celestron.com
Period Error Correction
Tracking Rates
Tracking Modes
Alignment Procedures
Complete Revised NGC Catalog
Complete Messier Catalog
Complete IC Catalog
Complete Caldwell
Abell Galaxies
Solar System objects
Famous Asterisms
Selected CCD Imaging Objects
Selected SAO Stars
RS-232 communication port on hand control, Autoguider Port, 2 Auxiliary Port, PC Port
Permanently programmable
Sidereal, Solar, Lunar
Alt-Az, EQ North and EQ South
Sky Align, Auto Two-Star Align, Two-Star Align, Solar System Align, EQ North Align
and EQ South Align
40,000+ objects, 99 user defined programmable objects.
Enhanced information on over 200 objects
Airy disk
The apparent magnitude that a star
would have if it were observed from a
years. The absolute magnitude of the Sun is
be visible on Earth on a clear moonless night
away from surface light.
The apparent size of a star’s disk produced even by
a perfect optical system. Since the star can never
be focused perfectly, 84 per cent of the light will
system of surrounding rings.
A telescope mounting using two
independent rotation axes allowing
movement of the instrument in Altitude
and Azimuth.
its Angular Distance above or below the celestial
astrology has nothing in common with astronomy.
unit (AU)
The distance between the Earth and the Sun.
The emission of light when charged particles from
the solar wind slams into and excites atoms and
molecules in a planet’s
upper atmosphere.
the horizon, measured from due north, between
the astronomical meridian (the vertical line passing
through the center of the sky and the north and
south points on the horizon) and the vertical line
containing the celestial body whose position is to
be measured.
Binary Stars
the larger the aperture, the greater the telescope’s
A measure of the relative brightness of a
by an observer on Earth.
Arc minute
a degree.
Arc second
night sky.
A small, rocky body that orbits a star.
Celestial Equator
Binary (Double) stars are pairs of stars that, because
of their mutual gravitational attraction, orbit around
more stars revolve around one another, it is called
50 percent of all stars belong to binary or multiple
systems. Systems with individual components that
can be seen separately by a telescope are called
visual binaries or visual multiples. The nearest “star”
to our solar system, Alpha Centauri, is actually our
of three stars, two very similar to our Sun and one
dim, small, red star orbiting around one another.
into two equal hemispheres.
>> www.celestron.com
Celestial pole
north or south pole onto the
celestial sphere.
An imaginary sphere surrounding the Earth,
concentric with the Earth’s center.
The act of putting a telescope’s optics into perfect
A reference line in the sky that starts at the North
celestial pole and ends at the South celestial pole and
the meridian starts from your Southern horizon and
passes directly overhead to the North celestial pole.
primarily looking for comets. Comets are hazy
that were not comets to help his search. This catalog
became the Messier Catalog, M1 through M110.
The angular distance of a celestial body
be said to correspond to latitude on the
surface of the Earth.
cloudy appearance.
North Celestial
The point in the Northern hemisphere around
which all the stars appear to rotate. This is
caused by the fact that the Earth is rotating on
an axis that passes through the North and
South celestial poles. The star Polaris lies less
than a degree from this point and is therefore
referred to as the “Pole Star”.
Although Latin for “new” it denotes a star that
suddenly becomes explosively bright at the end of its
life cycle.
yearly path of the Sun against the stars.”
A telescope mounting in which the instrument
is set upon an axis which is parallel to the
equal to the observer’s latitude.
Focal length
The distance between a lens (or mirror) and the point
to focus. The focal length divided by the aperture of
the mirror or lens is termed the focal ratio.
Open Cluster
Term used to refer to a computerized telescope
or to the act of slewing (moving) a computerized
Jovian Planets
Any of the four gas giant planets that are at a greater
distance form the Sun than the terrestrial planets.
a triangle from which the apex angle (the parallax)
if the length of the baseline between the observing
positions is known and the angular direction of the
has been measured. The traditional method in
astronomy of determining the distance to a celestial
Refers to a group of eyepieces that all require the
same distance from the focal plane of the telescope
to be in focus. This means when you focus one
parfocal eyepiece all the other parfocal eyepieces, in
a particular line of eyepieces, will be in focus.
The distance at which a star would show parallax
km. (Apart from the Sun, no star lies within one
parsec of us.)
Point Source
because it to too far away or too small is considered
a point source. A planet is far away but it can be
resolved as a disk. Most stars cannot be resolved as
disks, they are too far away.
Kuiper Belt
A region beyond the orbit of Neptune extending
to about 1000 AU which is a source of many short
period comets.
Light–Year (ly)
>> www.celestron.com
along the plane of the Milky Way. Most have
an asymmetrical appearance and are loosely
assembled. They contain from a dozen to many
hundreds of stars.
Magnitude is a measure of the brightness of a
celestial body. The brightest stars are assigned
magnitude 1 and those increasingly fainter from
2 down to magnitude 5. The faintest star that can
Each magnitude step corresponds to a ratio of 2.5 in
brightness. Thus a star of magnitude 1 is 2.5 times
brighter than a star of magnitude 2, and 100 times
brighter than a magnitude 5 star. The brightest star,
apparent magnitude scale is arbitrary.
A telescope in which the light is collected by means
of a mirror.
The minimum detectable angle an optical system
to the minimum angle, resolution. The larger the
aperture, the better the resolution.
The angular distance of a celestial
seconds along the Celestial Equator eastward
from the Vernal Equinox.
Sidereal Rate
This is the angular speed at which the Earth is
rotating. Telescope tracking motors drive the
telescope at this rate. The rate is 15 arc
seconds per second or 15 degrees per hour.
The boundary line between the light and dark
portion of the Moon or a planet.
A star whose brightness varies over time due to
either inherent properties of the star or something
eclipsing or obscuring the brightness of the star.
Waning Moon
The period of the Moon’s cycle between
full and new, when its illuminated portion
is decreasing.
Waxing Moon
The period of the Moon’s cycle between
new and full, when its illuminated portion
is increasing.
Rated the most important advance in optics.
in 200 years, the Schmidt telescope combines
for photographic purposes. It was invented in
1930 by Bernhard Voldemar Schmidt (1879-1935).
Variable Star
The point on the Celestial Sphere directly above the
The zodiac is the portion of the Celestial Sphere that
lies within 8 degrees on either side of the Ecliptic.
The apparent paths of the Sun, the Moon, and the
planets, with the exception of some portions of the
path of Pluto, lie within this band. Twelve divisions,
or signs, each 30 degrees in width, comprise the
zodiac. These signs coincided with the zodiacal
constellations about 2,000 years ago. Because of the
Precession of the Earth’s axis, the Vernal Equinox
has moved westward by about 30 degrees since
longer coincide with the constellations.
The totality of astronomical things, events, relations
>> www.celestron.com
You can control your NexStar telescope with a computer via the RS-232
port on the computerized hand control and using an optional RS-232
popular astronomy software programs.
Communication Protocol
‡•…”‹’–‹‘ ‘ƒ†
GoTo Azm-Alt
B12AB, 4000
GoTo Ra-Dec
R34AB, 12CE
Get Azm-Alt
12AB, 4000#
Get RA-Dec
34AB, 12CE#
Cancel GoTo
Is GoTo in Progress
Useful to check communication
10 characters sent.
B=Command, 12AB=Azm,
comma, 4000=Alt.
If command conflicts
with slew limits,
there will be no action.
Scope must be aligned.
If command conflicts with
slew limits, there will be
no action.
10 characters returned,
12AB=Azm, comma,
4000=Alt, #
Scope must be aligned
# or 1#
0=No, 1=Yes
HC version
Stop/Start Tracking
x = 0 (Tracking off)
x = 1 (Alt-Az on)
x = 2 (EQ-N)
x = 3 (EQ-S)
32-bit GoTo RA-Dec
32-bit get RA-Dec
32-bit GoTo Azm-Alt
32-bit get Azm-Alt
Version 1.6
Alt-Az tracking
requires alignment
The last two characters
will always be zero.
The last two characters
will always be zero.
4-4 Modular
Phone Jack
DB9 Pin 3
PC Transmit
DB9 Pin 5
>> www.celestron.com
DB9 Pin 2
PC Receive
>> www.celestron.com
>> www.celestron.com
>> www.celestron.com
>> www.celestron.com
>> www.celestron.com
>> www.celestron.com
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>> www.celestron.com
Jan 01-Jan 05
Apr 16-Apr 25
Apr 15-Apr 28
Apr 19-May 28
June Bootids
Jun 26-Jul 02
July Phoenicids
Jul 10-Jul 16
Southern delta-Aquarids
Jul 12-Aug 19
Jul 17-Aug 24
Aug 25-Sep 05
Oct 06-Oct 10
Oct 02-Nov 07
Nov 14-Nov 21
Nov 15-Nov 25
Nov 28-Dec 09
Dec 01-Dec 15
Dec 07-Dec 17
Dec 17-Dec 26
* These meteor showers have the potential of becoming meteor storms with
displays of thousands of meteors per hour.
2001 Dec 14
2001 Jun 21
2002 Dec 04
2002 Jun 10
2003 May 31
2003 Nov 23
2005 Apr 08
2006 Mar 29
2008 Aug 01
2009 Jul 22
2010 Jul 11
2012 May 20
2012 Nov 13
2013 May 10
2014 Oct 23
2015 Mar 20
2016 Mar 09
2017 Aug 21
2019 Jul 02
2020 Dec 14
North America, Hawaii
South Africa, Madagascar
S. Africa, Indonesia, Australia
West, Midwest, Hawaii, Alaska
Australia, New Zealand, S. America
Florida, Southwest
Africa, Europe, Asia
Europe, Asia
Asia, Hawaii
South America
West, Hawaii, Alaska
Australia, S. America
Australia, N.Z.
West, Midwest, Alaska
Europe, N. Africa, Asia
Hawaii, Alaska
Across the U.S.!
S. America
S. America
>> www.celestron.com
A. Celestron warrants this telescope to be free from defects in materials
and workmanship for two years. Celestron will repair or replace such
product or part thereof which, upon inspection by Celestron, is found
to be defective in materials or workmanship. As a condition to the
obligation of Celestron to repair or replace such product, the product
must be returned to Celestron together with proof-of-purchase
satisfactory to Celestron.
B. The Proper Return Authorization Number must be obtained from
to receive the number to be displayed on the outside of your
shipping container.
All returns must be accompanied by a written statement setting forth
the name, address and daytime telephone number of the owner,
together with a brief description of any claimed defects. Parts or
product for which replacement is made shall become the property
of Celestron.
the event repair or replacement shall require more than thirty days,
Celestron shall notify the customer accordingly. Celestron reserves
the right to replace any product which has been discontinued from its
product line with a new product of comparable value and function.
Some states do not allow the exclusion or limitation of incidental or consequential damages or limitation on how long
an implied warranty lasts, so the above limitations and exclusions may not apply to you.
Celestron reserves the right to modify or discontinue, without prior notice to you, any model or style telescope.
Customer Service Department
2835 Columbia Street
Torrance, CA 90503
This warranty supersedes all other product warranties.
>> www.celestron.com
FCC Statement
This device complies with Part 15 of FCC Rules.
Operation is subject to the following two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including
interference that may cause undesired operation.
©2011 Celestron
Product design and specifications are subject to change
without prior notification.
Designed and intended for those 13 years of age and older.
Superior flat-field, coma-free imaging
by the Celestron Engineering Team
Ver. 04-2013, For release in April 2013.
The Celestron EdgeHD A Flexible
Imaging Platform at an Affordable Price
By the Celestron Engineering Team
The Celestron EdgeHD is an advanced, flat-field, aplanatic
series of telescopes designed for visual observation and imaging
with astronomical CCD cameras and full-frame digital SLR
cameras. This paper describes the development goals and
design decisions behind EdgeHD technology and their practical
realization in 8-, 9.25-, 11-, and 14-inch apertures. We include
cross-sections of the EdgeHD series, a table with visual and
imaging specifications, and comparative spot diagrams for
the EdgeHD and competing “coma-free” Schmidt-Cassegrain
designs. We also outline the construction and testing process for
EdgeHD telescopes and provide instructions for placing sensors
at the optimum back-focus distance for astroimaging.
The classic Schmidt-Cassegrain telescope (SCT) manufactured
by Celestron served an entire generation of observers and astrophotographers. With the advent of wide-field and ultra-wide-field
eyepieces, large format CCD cameras, and full frame digital SLR
cameras, the inherent drawbacks of the classic SCT called for a
new design. The EdgeHD is that new design. The EdgeHD offers clean, diffraction-limited images for high power observation
of the planets and the Moon. As an aplanatic, flat-field astrograph, the EdgeHD’s optics provide tight, round, edge-to-edge
star images over a wide, 42mm diameter flat field of view for
stunning color, monochrome, and narrow-band imaging of deep
sky objects.
The story of the EdgeHD began with our setting performance
goals, quality goals, and price goals. Like the classic SCT, the
new Celestron optic would need to be light and compact.
Optically, we set twin goals. First, the new telescope had to
be capable of extraordinary wide-field viewing with advanced
eyepiece designs. Second, the optic had to produce sharp-tothe-edge astrophotography with both digital SLR cameras and
astronomical CCD cameras. Finally, we wanted to leverage
Celestron’s proven ability to manufacture high-performance
telescopes at a consumer-friendly price point. In short, we sought
to create a flexible imaging platform at a very affordable price.
Given an unlimited budget, engineering high-performance optics
is not difficult. The challenge Celestron accepted was to
control the price, complexity, and cost of manufacture without
compromising optical performance. We began with a comprehensive review of the classic SCT and possible alternatives.
Our classic SCT has three optical components: a spherical
primary mirror, a spherical secondary mirror, and a corrector plate
with a polynomial curve. As every amateur telescope maker and
professional optician knows, a sphere is the most desirable
optical figure. In polishing a lens or mirror, the work piece moves
over a lap made of optical pitch that slowly conforms to the glass
surface. Geometrically, the only surfaces that can slide freely
against one another are spheres. Any spot that is low relative to
the common spherical surface receives no wear; any spot that is
higher is worn off. Spherical surfaces result almost automatically.
2 I The Celestron EdgeHD
A skilled optician in a well-equipped optical shop can reliably
produce near-perfect spherical surfaces. Furthermore, by
comparing an optical surface against a matchplate—a precision
reference surface—departures in both the radius and sphericity
can be quickly assessed.
In forty years of manufacturing its classic Schmidt-Cassegrain
telescope, Celestron had fully mastered the art of making
large numbers of essentially perfect spherical primary and
secondary mirrors.
In addition, Celestron’s strengths included the production of
Schmidt corrector plates. In the early 1970s, Tom Johnson,
Celestron’s founder, perfected the necessary techniques.
Before Johnson, corrector plates like that on the 48-inch
Schmidt camera on Palomar Mountain required many long
hours of skilled work by master opticians. Johnson’s innovative
production methods made possible the volume production of a
complex and formerly expensive optical component, triggering
the SCT revolution of the 1970s.
For more than forty years, the SCT satisfied the needs of
visual observers and astrophotographers. Its performance
resulted from a blend of smooth spherical surfaces and
Johnson’s unique method of producing the complex curve
on the corrector with the same ease as producing spherical
surfaces. As the 21st century began, two emerging technologies
—wide-field eyepieces and CCD cameras—demanded highquality images over a much wider field of view than the classic SCT could provide. Why? The classic SCT is well-corrected
optically for aberrations on the optical axis, that is, in the exact
center of the field of view. Away from the optical axis, however,
its images suffer from two aberrations: coma and field curvature.
Coma causes off-axis star images to flare outward; field curvature
causes images to become progressively out of focus away from
the optical axis. As wide-field eyepieces grew in popularity, and
as observers equipped themselves with advanced CCD cameras,
the classic SCT proved inadequate. To meet the requirements of
observers, we wanted the new Celestron optic to be both free of
coma and to have virtually zero field curvature.
EdgeHD Series
Edge HD 800
Edge HD 925
Edge HD 1100
Edge HD 1400
FIGURE 1. Celestron’s EdgeHD series consists of four aplanatic telescopes with 8-, 9.25-, 11-, 14-inch apertures. The optical design
of each instrument has been individually optimized to provide a flat, coma-free focal plane. Each EdgeHD optic produces sharp images
to the edge of the view with minimal vignetting.
The Celestron EdgeHD 3
For those not familiar with the art of optical design, this brief
primer explains what aberrations are and how they appear in a
telescopic image.
Coma is an off-axis aberration that occurs when the rays from
successive zones are displaced outward relative to the principal
(central) ray. A star image with coma appears to have wispy “hair”
or little “wings” extending from the image. In a coma-free optical
system, rays from all zones are centered on the (central) ray, so
stars appear round across the field
Field curvature occurs when the best off-axis images in an optical
system focus ahead or behind the focused on-axis image. The
result is that star images in the center of the field of view are
sharp, but off-axis images appear more and more out of focus. A
telescope with no field curvature has a “flat field,” so images are
sharp across the whole field of view.
In the Schmidt-Cassegrain, spherochromatism is present, but
not deleterious in designs with modest apertures and focal
ratios. It occurs because the optical “power” of the Schmidt
corrector plate varies slightly with wavelength. Only in very large
apertures or fast SCTs does spherochromism become a problem.
We did not take lightly the task of improving the classic SCT. Its
two spherical mirrors and our method of making corrector lenses
allowed us to offer a high-quality telescope at a low cost. We
investigated the pros and cons of producing a Ritchey-Chrétien
(R-C) Cassegrain, but the cost and complexity of producing its
hyperbolic mirrors, as well as the long-term disadvantages of
an open-tube telescope, dissuaded us. We also designed and
produced two prototype Corrected Dall-Kirkham (CDK)
telescopes, but the design’s ellipsoidal primary mirror led
inevitably to a more expensive instrument. While the R-C and
CDK are fine optical systems, we wanted to produce equally fine
imaging telescopes at a more consumer-friendly price.
As we’ve already noted, our most important design goal for the
new telescope was to eliminate coma and field curvature over
a field of view large enough to accommodate a top-of-theline, full-frame digital SLR camera or larger astronomical CCD
camera. This meant setting the field of view at 42 mm in
diameter. Of course, any design that would satisfy the
full-frame requirement would also work with the less expensive
APS-C digital SLR cameras (under $800) and less expensive
astronomical CCD cameras (under $2,000). There are several
ways to modify the classic SCT to reduce or eliminate coma.
4 I The Celestron EdgeHD
Unfortunately, these methods do not address the problem of field
curvature. For example, we could replace either the spherical
primary or secondary with an aspheric (i.e., non-spherical)
mirror. Making the smaller secondary mirror into a hyperboloid
was an obvious choice. Although this would have given us a
coma-free design, its uncorrected field curvature would leave
soft star images at the edges of the field. We were also
concerned that by aspherizing the secondary, the resulting
coma-free telescopes would potentially have zones that would
scatter light and compromise the high-power definition that
visual observers expect from an astronomical telescope.
Furthermore, the aspheric secondary mirror places demands
on alignment and centration that often result in difficulty
maintaining collimation.
The inspiration for the EdgeHD optics came from combining
the best features of the CDK with the best features of the
classic SCT. We placed two small lenses in the beam of light
converging toward focus and re-optimized the entire telescope
for center-to-edge performance. In the EdgeHD, the primary and
secondary mirrors retain smooth spherical surfaces, and the
corrector plate remains unchanged. The two small lenses do
the big job of correcting aberrations for a small increment in
cost to the telescope buyer. Furthermore, because it retains key
elements of the classic SCT, the EdgeHD design is compatible
with the popular Starizona Hyperstar accessory.
100 μm
5.00 mm
10.00 mm
15.00 mm
20.00 mm
Off-axis distance (millimeters)
FIGURE 2. Matrix spot diagrams compare the center-to-edge optical performance of the classic SCT, “coma-free” SCT, and EdgeHD.
The EdgeHD clearly outperforms the other optical systems. The classic SCT shows prominent coma. The “coma-free” SCT is indeed
free of coma, but field curvature causes its off-axis images to become diffuse and out of focus. In comparison, the EdgeHD’s spot pattern
is tight, concentrated, and remains small from on-axis to the edge of the field.
The Celestron EdgeHD 5
Optical design involves complex trade-offs between optical
performance, mechanical tolerances, cost, manufacturability, and
customer needs. In designing the EdgeHD, we prioritized optical
performance first: the instrument would be diffraction-limited on
axis, it would be entirely coma-free, and the field would be flat
to the very edge. (Indeed, the name EdgeHD derives from our
edge-of-field requirements.)
Figure 2 shows ray-traced spot diagrams for the 14-inch
aperture classic SCT, coma-free SCT, and EdgeHD. All three are
14-inch aperture telescopes. We used ZEMAX® professional
optical ray-trace software to design the EdgeHD and produce
these ray-trace data for you.
Each spot pattern combines spots at three wavelengths: red
(0.656μm), green (0.546μm), and blue (0.486μm) for five field
positions: on-axis, 5mm, 10mm, 15mm, and 20mm off-axis
distance. The field of view portrayed has diameter of 40mm—
just under the full 42mm image circle of the EdgeHD—and
the wavelengths span the range seen by the dark-adapted
human eye and the wavelengths most often used in deep-sky
astronomical imaging.
In the matrix of spots, examine the left hand column. These are
the on-axis spots. The black circle in each one represents the
diameter of the Airy disk. If the majority of the rays fall within
the circle representing the Airy disk, a star image viewed at
high power will be limited almost entirely by diffraction, and is
therefore said to be diffraction-limited. By this standard, all three
SCT designs are diffraction-limited on the optical axis. In each
case, the Schmidt corrector removes spherical aberration for
green light. Because the index of refraction of the glass used in
the corrector plate varies with wavelength, the Schmidt corrector
allows a small amount of spherical aberration to remain in red
and blue light. This aberration is called spherochromatism, that
is, spherical aberration resulting from the color of the light. While
the green rays converge to a near-perfect point, the red and
blue spot patterns fill or slightly overfill the Airy disk. Numerically,
the radius of the Airy disk is 7.2μm, (14.4μm diameter) while the
root-mean-square radius of the spots at all three wavelengths is
5.3μm (10.6μm diameter). Because the human eye is considerably
more sensitive to green light than it is to red or blue, images in
the eyepiece appear nearly perfect even to a skilled observer.
Spherochromatism depends on the amount of correction, or
the refractive strength, of the Schmidt lens. To minimize
spherochromatism, high-performance SCTs have traditionally
been ƒ/10 or slower. When pushed to focal ratios faster than
ƒ/10 (that is, when pushed to ƒ/8, ƒ/6, etc.) spherochromatism
increases undesirably.
Next, comparing the EdgeHD with the classic SCT and the
“coma-free” SCT, you can see that off-axis images in the classic
SCT images are strongly affected by coma. As expected, the
images in the coma-free design do not show the characteristic
comatic flare, but off-axis they do become quite enlarged. This is
the result of field curvature.
Figure 3 illustrates how field curvature affects off-axis images.
In an imaging telescope, we expect on-axis and off-axis rays
to focus on the flat surface of a CCD or digital SLR image
sensor. But unfortunately, with field curvature, off-axis rays come
to sharp focus on a curved surface. In a “coma-free” SCT, your
off-axis star images are in focus ahead of the CCD.
At the edge of a 40mm field, the “coma-free” telescope’s stars
have swelled to more than 100μm in diameter. Edge-of-field star
images appear large, soft, and out of focus.
6 I The Celestron EdgeHD
Meanwhile, at the edge of its 40mm field, the EdgeHD’s
images have enlarged only slightly, to a root-mean-square
radius of 10.5μm (21μm diameter). But because the green rays
are concentrated strongly toward the center, and because every
ray, including the faint “wings” of red light, lie inside a circle only
50μm in diameter, the images in the EdgeHD have proven to be
quite acceptable in the very corners of the image captured by a
full-frame digital SLR camera.
Field curvature negatively impacts imaging when you want
high-quality images across the entire field of view. Figures 4 and
5 clearly demonstrate the effects of field curvature in 8- and
14-inch telescopes. Note how the spot patterns change with
off-axis distance and focus. A negative focus distance means
closer to the telescope; a positive distance mean focusing
outward. In the EdgeHD, the smallest spots all fall at the same
focus position. If you focus on a star at the center of the field,
stars across the entire field of view will be in focus.
In comparison, the sharpest star images at the edge of the
field in the “coma-free” telescope come to focus in front of the
on-axis best focus. If you focus for the center of the image, star
images become progressively enlarged at greater distances. The
best you can do is focus at a compromise off-axis distance, and
accept slightly out-of-focus stars both on-axis and at the edge
of the field.
Any optical designer with the requisite skills and optical ray-tracing
software can, in theory, replicate and verify these results. The
data show that eliminating coma alone is not enough to guarantee
good images across the field of view. For high-performance
imaging, an imaging telescope must be diffraction-limited
on-axis and corrected for both coma and field curvature off-axis.
That’s what you get with the EdgeHD, at a very affordable price.
Field Curvature
Telescope with Field Curvature
Flat-Field Telescope
FIGURE 3. In an optical system with field curvature, objects
are not sharply focused on a flat surface. Instead, off-axis rays
focus behind or ahead of the focus point of the on-axis rays at
the center of the field. As a result, the off-axis star images are
enlarged by being slightly out of focus.
Centering the primary mirror is even more demanding. In
the classic SCT, the primary mirror is attached to a sliding
“focus” tube. When you focus the telescope, the focus knob
moves the primary mirror longitudinally. When you reverse the
direction of focus travel, the focus tube that carries the primary
can “rock” slightly on the baffle tube, causing the image to shift.
In the classic SCT, the shift does not significantly affect on-axis
image quality. However, in the EdgeHD, off-axis images could
be affected. Because the baffle tube carries the sub-aperture
corrector inside and the primary mirror on the outside, we
manufacture it to an extremely tight diametric tolerance.
The tube that supports the primary was redesigned with a
centering alignment flange, which contacts the optical (front)
surface of the primary mirror. When the primary mirror is assembled
onto the focus tube and secured with RTV adhesive, this small
mechanical change guarantees precise optical centration.
Following assembly, the focus tube carrying the primary is placed
in a test jig. We rotate the mirror and verify that the primary is
precisely squared-on to ensure that the image quality expected
from the optics is maintained.
To ensure that the completed EdgeHD telescope delivers the
full potential of the optical design, we also redesigned key
mechanical components. With classic SCT designs, for example,
an observer could bring the optical system to focus at different
back focus distances behind the optical tube assembly,
changing effective focal length of the telescope. This caused
on-axis spherical aberration and increased the off-axis
aberration. In the EdgeHD series, the back focus distance is
optimized and set for one specific distance. Every EdgeHD
comes equipped with a visual back that places the eyepiece
at the correct back focus distance, and our Large T-Adapter
accessory automatically places digital SLR cameras at the
optimum back focus position.
As part of the optical redesign, we placed the primary and
secondary mirrors closer than they had been in the classic SCT,
and designed new baffle tubes for both mirrors that allow a larger illuminated field of view.
To ensure full compatibility with the remarkable Starizona Hyperstar accessory that enables imaging at ƒ/1.9 in the EdgeHD 800
and ƒ/2.0 in the EdgeHD 925, 1100, and 1400, all EdgeHDs
have a removable secondary mirror.
In any optical system with a moveable primary mirror, focus
shift—movement of the image when the observer changes
focusing direction—has been an annoyance. In Celestron’s SCT
and EdgeHD telescopes, we tightened the tolerances. During
assembly and testing, we measure the focus shift; any unit with
more than 30 arcseconds focus shift is rejected and returned to
an earlier stage of assembly for rework.
Because it covers a wide field of view, the optical elements of
the EdgeHD must meet centering and alignment tolerances
considerably tighter than those of the classic SCT design. For
example, because the corrector plate must remain precisely
centered, we secure it with alignment screws tipped with soft
Nylon plastic. The screws are set on the optical bench during
assembly while we center the corrector plate. Once this
adjustment is perfect, the screws are tightened and sealed with
Loctite® to secure the corrector in position. This seemingly small
mechanical change ensures that the corrector plate and the
secondary mirror mounted on the corrector plate stay in
permanent optical alignment.
In the classic SCT, astrophotographers sometimes experience
an image shift as the telescope tracks across the meridian. The
focus mechanism serves as one support point for the mirror. In
the EdgeHD, we added two stainless steel rods to the back of
the cell that supports the primary mirror. When the two mirror
clutches at the back of the optical tube assembly are engaged,
aluminum pins press against the stainless steel rods, creating
two additional stabilizing support points (see Figure 6).
8” ƒ/10 Coma-Free SCT
-0.8 mm
-0.4 mm
0.0 mm
+0.4 mm
8” ƒ/10 Flat-Field EdgeHD
+0.8 mm
-0.8 mm
-0.4 mm
0.0 mm
+0.4 mm
+0.8 mm
3.5 mm
7 mm
10.5 mm
14 mm
Spot diagrams plotted for 0.0, 3.5, 7, 10.5, and 14 mm off-axis; showing λ = 0.486, 0.546, and 0.656 μm.
FIGURE 4. Compare star images formed by a 8-inch coma-free SCT with those formed by an EdgeHD. The sharpest star images in
the coma-free SCT follow the gray curve, coming to focus approximately 0.6mm in front of the focal plane. In the EdgeHD, small, tight
star images are focused at the focal plane across the field of view, meaning that your images will be crisp and sharp to the very edge.
The Celestron EdgeHD 7
14” ƒ/10 Coma-Free SCT
-0.8 mm
-0.4 mm
0.0 mm
+0.4 mm
14” ƒ/11 Flat-Field EdgeHD
+0.8 mm
-0.8 mm
-0.4 mm
0.0 mm
+0.4 mm
+0.8 mm
5 mm
10 mm
15 mm
20 mm
Spot diagrams plotted for 0.0, 5, 10, 15, and 20mm off-axis; showing λ = 0.486, 0.546, and 0.656μm.
FIGURE 5. In a 14-inch coma-free SCT, the smallest off-axis star images lie on the curved focal surface indicated by the gray line.
Since CCD or digital SLR camera sensors are flat, so star images at the edge of the field will be enlarged. In the aplanatic EdgeHD
design, the smallest off-axis images lie on a flat surface. Stars are small and sharp to the edge of the field.
Telescope tubes must “breathe” not only to enable cooling, but
also to prevent the build-up of moisture and possible condensation
inside the tube. In the classic SCT, air can enter through the open
baffle tube. In the EdgeHD, the sub-aperture lenses effectively
close the tube. To promote air exchange, we added ventilation
ports with 60μm stainless steel mesh that keeps out dust but
allows the free passage of air.
In a telescope designed for imaging, users expect to
attach heavy filter wheels, digital SLRs, and astronomical CCD
cameras. We designed the rear threads of the EdgeHD 925,
1100, and 1400 telescopes with a heavy-duty 3.290×16 tpi
thread, and we set the back focus distance to a generous 5.75
inches from the flat rear surface of the baffle tube locking nut.
The rear thread on the EdgeHD 800 remains the standard
2.00×24 tpi, and the back-focus distance is 5.25 inches.
Many suppliers offer precision focusers, rotators, filter wheels,
and camera packages that are fully compatible with the
heavy-duty rear thread and back focus distance of the EdgeHD.
FIGURE 6. The mirror clutch mechanism shown in this crosssection prevents the primary mirror from shifting during the long
exposures used in imaging.
Each EdgeHD has five optical elements: an aspheric Schmidt
corrector plate, a spherical primary mirror, a spherical secondary
mirror, and two sub-aperture corrector lenses. Each element is
manufactured to meet tight tolerances demanded by a highperformance optical design. Celestron applies more than forty
years of experience in shaping, polishing, and testing astronomical
telescope optics to every one of the components in each EdgeHD
telescope. Our tight specifications and repeated, careful testing
guarantee that the telescope will not only perform well for highpower planetary viewing, but will also cover a wide-angle field
for superb edge-to-edge imaging. Nevertheless, we don’t take
this on faith; both before and after assembly, we test and tune
each set of optics.
8 I The Celestron EdgeHD
Celestron’s founder, Tom Johnson, invented the breakthrough
process used to make Celestron’s corrector plates. Over the
years, his original process has been developed and refined. At
present, we manufacture corrector plates with the same level of
ease, certainty, and repeatability that opticians expect when they
are producing spherical surfaces.
Each corrector plate begins life as a sheet of water-white, hightransmission, low-iron, soda-lime float glass. In manufacturing
float glass, molten glass is extruded onto a tank of molten tin,
where the glass floats on the dense molten metal. The molten
tin surface is very nearly flat (its radius of curvature is the radius
of planet Earth!), and float glass is equally flat.
We cut corrector blanks from large sheets of the glass, then run
them through a double-sided surfacing machine to grind and
polish both surfaces to an optical finish. The blanks are inspected
and any with defects are discarded.
The Johnson/Celestron method for producing the polynomial
aspheric curve is based on precision “master blocks” with the
exact inverse of the desired curve. We clean the master block
and corrector blank, and then, by applying a vacuum from the
center of the block, pull them into intimate optical contact,
excluding any lint, dust, or air between them, gently bending
the flat corrector blank to match the reverse curve of the block.
We then take the combined master block and corrector blank
and process the top surface of the corrector to a polished
concave spherical surface. With the corrector lens still on the
master block, an optician tests the radius and figure of the new
surface against a precision reference matchplate (also known as
an optical test plate or test glass) using optical interference to
read the Newton’s rings or interference fringes, as shown in
Figure 7. If the surface radius lies within a tolerance of zero to
three fringes (about 1.5 wavelengths of light, or 750nm concave),
and the surface irregularity is less than half of one fringe (¼–
wavelength of light), the corrector is separated from the master
block. The thin glass springs back to its original shape, so that
the side that was against the master block becomes flat and the
polished surface assumes the profile of a Schmidt corrector lens.
The corrector is tested again, this time in a double-pass auto
collimator. Green laser light at 532nm wavelength (green)
enters through an eyepiece, strikes an EdgeHD secondary and
primary mirror, passes through the corrector lens under test,
reflects from a precision optical flat, goes back through the
corrector to reflect again from the mirrors, and finally back to
focus. Because the light passes twice through the Schmidt
corrector lens, any errors are seen doubled. The double-pass
autocollimation test (see Figure 9) ensures that every Schmidt
corrector meets the stringent requirements of an EdgeHD
optical system.
transfers them to an abrasive free room where they are polished
to a precise spherical surface. Each mirror is checked for both
radius and optical spherical figure against a convex precision
reference matchplate. When the interference fringes indicate
the radius is within ±1 fringe from the nominal radius and the
surface irregularity is less than one fourth of one fringe, the
mirror receives a final check using the classic mirror-maker’s
null test familiar to every professional optican. Afterwards,
every primary mirror is taken to the QA Interferometry Lab—shown
in Figure 10—where the surface irregularity of each mirror is
verified, via interferometer, to be within specification.
The smaller secondary mirrors are also made of low-expansion
borosilicate glass. Like the primaries, the secondaries are edged
and centered, then ground and polished. The secondary is a
convex mirror so during manufacture it is tested against a
concave precision reference matchplate to check both its radius
of curvature and figure. The secondary mirrors are also brought
to the QA Interferometry Lab where the radius and irregularity of
each mirror is verified through interferometric measurement to
assure that each one lies within specification.
When we designed the EdgeHD optical system, we strongly
favored spherical surfaces because a sphere can be tested by
optical interference to high accuracy in a matter of minutes. If we
had specified a hyperboloidal surface for the secondary mirror,
we would have been forced to use slower, less accurate testing
methods that might miss zonal errors. Furthermore, coma-free
SCT designs with hyperboloidal mirrors still suffer from field
curvature—an aberration that we specifically wished to avoid in
the EdgeHD design.
Finally, the sub-aperture corrector lenses are made using the
same manufacturing techniques used for high-performance
refractor objectives. The EdgeHD design specifies optical glass
from Schott AG. The 8-, 9.25-, and 11-inch use N-SK2 and K10
glasses, while the 14-inch uses N-SK2 and N-BALF2 glasses.
To ensure homogeneity, optical glass is made in relatively small
batches, extruded in boules. The raw glass is then diamondmilled to the correct diameter, thickness, and radius. Each lens
blank is blocked, ground, and polished, then the radius and figure
are compared to matchplates to ensure they meet EdgeHD’s
tight tolerances.
Our assembly workstations resemble the optical benches used
to qualify corrector plates. The primary mirror and corrector plate
slip into kinematic support jigs, and we place the secondary
mirror in its holder. The sub-aperture corrector lenses meet
specifications so reliably that a master set is used in the assembly workstation. Laser light from the focus position passes in
reverse through the optics, reflects from a master autocollimation
flat, then passes back through the optics. Tested in autocollimation,
the optician can see and correct surface errors considerably
smaller than a millionth of an inch.
FIGURE 7. Matchplates use interference fringes to check
the radius and smoothness of the correction. In this picture, a
corrector blank is attached to a master block. The matchplate
rests on top; interference fringes appear as green and blue
circles. The circular pattern indicates a difference in radius.
Primary mirrors begin as precision-annealed molded castings of
low-expansion borosilicate glass with a weight-saving conical
back surface and a concave front surface. The molded casting
is edged round, its central hole is cored, and the radius of the
front surface is roughed in. Celestron grinds the front surface of
primary mirrors with a succession of progressively finer diamond
abrasive pellet tools using high-speed spindle machines, then
If the combined optics set shows any slight residual under-or
over-correction, zones, astigmatism, upturned or downturned
edges, holes, or bulges, the optician marks the Foucault test
shadow transitions on the secondary mirror, then removes the
secondary mirror from the test fixture and translates these
markings into a paper pattern. The pattern is pressed against
a pitch polishing tool, and the optician applies corrective polishing
to the secondary mirror—as we show in Figure 11—until the
optical system as a whole displays a perfectly uniform illumination
(no unwanted zones or shadows) under the double-pass
Foucault test and smooth and straight fringes under the doublepass Ronchi test. The in-focus Airy disk pattern is evaluated for
roundness, a single uniform diffraction ring, and freedom from
scattered light. In addition, the intra- and extra-focal diffraction
pattern must display the same structure and central obscuration
on both sides of focus, and it must appear round and uniform.
The Celestron EdgeHD 9
FIGURE 8. After all the testing is done, the ultimate test is the night sky. This close-up image of the Pelican Nebula testifies to the
EdgeHD’s ability to focus clean, neat, round star images from center to edge. The telescope was a 14-inch EdgeHD on a CGE Pro
Mount; the CCD camera was an Apogee U16m. The mage above shows a 21.5×29.8mm section cropped from the original 36.8mm
square image.
10 I The Celestron EdgeHD
Autocollimation Testing
Telescope being checked
Precision optical flat
Eyepiece and Ronchi grating
Green Laser (532 nm)
FIGURE 9. In autocollimation testing, light goes through an
optical system, reflects from a plane mirror, and passes through
again. This super-sensitive test method doubles the apparent size
of all errors.
After we remove each set of optics from the autocollimator, we
send the components to our in-house coating chamber. Here,
the primary and secondary mirrors receive their high-reflectance
aluminum coatings, and the corrector lens is anti-reflectance
coated. Each set of optics is then installed into an optical tube
assembly (OTA).
Completed OTAs undergo the Visual Acceptance Test. In a
temperature-stabilized optical test tunnel, green laser light at
532nm wavelength is reflected from a precision paraboloidal
mirror to act as an artificial star. With a high-power ocular, a QA
Inspector views the artificial star critically.
To pass the Visual Acceptance Test, an optical tube assembly
must meetthe following requirements:
• The in-focus Airy disk must be round, free of scattered light
around the disk, and display only one bright ring.
• Inside and outside focus, the diffraction patterns must be
round, uniform, and appear similar on both sides of focus.
• Observed with a 150 line-pairs-per-inch Ronchi grating, the
bands must be straight, uniformly spaced, and high in contrast.
Because its optics have been tested and tuned in error-revealing
double-pass mode, and because each assembled OTA has been
tested again and qualified visually, the telescope’s images should
be flawless when observing and imaging the night sky.
FIGURE 10. We test all of our primary mirrors on an optical
bench by means of laser interferometry. In the picture, stacks of
polished primary mirrors await testing.
Before it can leave Celestron’s facilities, every EdgeHD must
pass its Final Acceptance Test, or FAT. We conduct the FAT on
an optical test bench in a specially-constructed temperaturecontrolled room (Figure 12). Rather than use laser light for this
test, we use white light so that the FAT reproduces the same
conditions an observer would experience while viewing or
photographing the night sky. To avoid placing any heat sources
in the optical path, the light for our artificial star is carried to the
focus of a precision parabolic mirror through a fiber-optic cable.
After striking the parabolic mirror, the parallel rays of light travel
down the optical bench to the EdgeHD under test, through the
telescope, to a full-frame format digital SLR camera placed at
its focus.
Using a set of kinematic test cradles, there is no need to change
the test configuration between different EdgeHD telescopes.
We simply place the telescope in its test cradle on the bench,
and it’s ready for testing. The Final Acceptance Test verifies an
EdgeHD’s ability to form sharp star images in the center and
on the edges of a full-frame (24×36mm format, with a 42mm
diagonal measurement) digital SLR camera. The QA Inspector
attaches the camera to the telescope, focuses carefully, and
takes an on-axis image. The telescope is then pointed so the
artificial star image falls in the corner of the frame, and without refocusing, the inspector takes another image. The process
is repeated for each corner of the camera frame, and another
picture is taken at the center of the frame.
FIGURE 11. To correct any remaining optical errors, the figure of
the secondary mirror is fine-tuned against the entire optical system
in double-pass autocollimation setup. This delicate match process
ensures that every telescope performs to the diffraction limit.
To pass the test, the telescope must form a sharp image at the
center of the field, at each corner of the camera frame, and
again at the center. The images are examined critically. To pass,
every one of the test images must be tight, round, and in perfect
focus. Any EdgeHD that does not pass the FAT is automatically
returned to the assembly room to recheck the collimation and
centering of its corrector plate. No EdgeHD can leave the
factory until it has passed its FAT.
The Celestron EdgeHD 11
Throughout the telescope-building process, we maintain a
quality-assurance paper trail for each instrument. All test
images are numbered and cross referenced. Should a telescope
be returned to Celestron for service, we can consult our records
to see how well it performed before it left our facility. Once a telescope has passed the FAT, we apply Loctite® to the set screws
to permanently hold the alignment of the corrector plate. The
instrument is then inspected carefully for cosmetic defects. It is
cleaned and packaged for shipment to our dealers and customers.
To your discerning eye—as an observer with experience—on a
night with steady air and good seeing, a properly cooled EdgeHD
performs exceptionally well on stars. You will see a round, clean
Airy disk, a single well-defined diffraction ring, and symmetrical
images inside and outside of focus. Every EdgeHD should
resolve double stars to the Dawes limit, reveal subtle shadings
in the belts of Jupiter, and reveal the Cassini Division in Saturn’s
rings. On deep-sky objects viewed with a high-quality eyepiece,
star images appear sharp and well defined to the edge of the
field of view. The EdgeHD reveals faint nebular details as fine as
the sky quality at the observing site will allow.
EdgeHD Field of View
42 mm ∅
FIGURE 12. In the Final Acceptance Test, the EdgeHD optics
must demonstrate the ability to form sharp images at the center
and in the corners of a Canon 5D Mark II full-frame digital SLR
camera, with a sensor that measures 42mm corner-to-corner.
Because both the Celestron EdgeHD and our classic SCTs
are diffraction-limited on-axis, their performance is essentially
the same for high-magnification planetary or lunar viewing,
splitting close double stars, or any other visual observing task
that requires first-rate on-axis image quality. However, the
EdgeHD outshines the classic SCT when it comes to observing
deep-sky objects with the new generation of high-performance
wide-field eyepieces.
The classic SCT exhibits off-axis coma and field curvature
which are absent from the EdgeHD design. Modern wide-field
eyepieces, such as the 23mm Luminos, have an apparent field
of view of 82 degrees, so they show you a larger swatch of
the sky. Gone are the light-robbing radial flares of coma and
annoying, out-of-focus peripheral images so sadly familiar
to observers. With the EdgeHD, stars are crisp and sharp to
the edge.
The back of the EdgeHD 800 features an industry standard
2.00×24 tpi threaded flange. A large retaining ring firmly
attaches the 1¼-inch visual back, and this accepts a 1¼-inch
Star Diagonal that will accept any standard 1¼-inch eyepiece.
The EdgeHD 925, 1100, and 1400 feature a heavy-duty flange
with a 3.290×16 tpi threaded flange. This oversize flange
allows you to attach heavy CCD cameras and digital SLR
cameras. For visual observing, use the adapter plate supplied
with each telescope to attach the Visual Back. The 2-inch XLT
Diagonal (also supplied with these telescopes) accepts eyepieces
with 1¼-inch and 2-inch barrels.
12 I The Celestron EdgeHD
Full-Frame DSLR
FIGURE 13. EdgeHD telescopes are designed to provide
good images across a flat 42mm diameter field of view.
Compare this with the size of a variety of image sensor formats.
The popular APS-C digital SLR format fits easily. The full-frame
DSLR format is fully covered. EdgeHD even covers the 36.8mm
square KAF-16803 format remarkably well.
Imaging with Celestron EdgeHD Telescopes
Focal Ratio
Focal Length
Secondary Ø
Back Focus
Thread Size
Image Circle
Linear Ø
Angular Ø
Airy Disk
Angular Ø
Linear Ø
Image Scale
(6.4 μm
34 %
2.00”-24 tpi
42mm Ø
68.0 arcmin
1.36” Ø
14.0μm Ø
36 %
3.29”-16 tpi
42mm Ø
62.2 arcmin
1.18” Ø
13.2μm Ø
33 %
3.29”-16 tpi
42mm Ø
51.8 arcmin
0.99” Ø
13.3μm Ø
3.29”-16 tpi
42mm Ø
37.4 arcmin
0.78” Ø
14.4μm Ø
The Ø symbol means diameter. Central obscuration is given as a percentage of the aperture.
The Rayleigh Limit for resolving doubles with equally bright components. The “ symbol means arcseconds.
The Celestron EdgeHD was designed and optimized for imaging
with astronomical CCD cameras, digital SLR cameras, video
astronomy sensors, electronic eyepieces, and webcams. We
designed the EdgeHD 800 to deliver the best images 5.25
inches (133.35mm) behind the surface of the telescope’s rear
cell 2.00×24 tpi threaded baffle tube lock nut. The EdgeHD
925, 1100, and 1400 form their best images 5.75 inches
(146.05mm) behind the telescope’s rear cell 3.290×16 tpi
threaded baffle tube lock nut. For best results, the image sensor
should be located within ±0.5mm of this back-focus distance.
It is easy to place a digital SLR (DSLR) camera at the proper
distance using the Small T-Adapter (item #93644) for the
EdgeHD 800, or the Large T-Adapter (item #93646) for the
EdgeHD 925, 1100, and 1400. The small adapter is 78.35mm
long while the large adapter adds 91.05mm, in both cases
placing the best focus 55mm behind the T-Adapter. Because
55mm is the industry standard T-mount to sensor distance, add
a T-Ring adapter (T-Ring for Canon EOS, item #93419; T-Ring
for Nikon, item #93402) and attach your camera to it. That’s
all there is to placing your digital SLR camera at the correct
back-focus location. (By the way, if you’ve never heard of the
T-mount system, you need to know about it. The T-mount is a
set of industry standard sizes and distances for camera lenses.
A standard T-mount thread (M42×0.75) is available for most
astronomical CCD cameras. The standard T-mount flange-tosensor distance is 55mm.)
The T-mount system also makes spacing an astronomical CCD
camera easy. Consult your CCD camera’s documentation to find
the flange-to-sensor distance for your CCD camera. Attaching
the Celestron T-Adapter to your EdgeHD gives you the standard
55mm spacing. If your CCD’s front flange-to-sensor distance
is 35mm, you need an additional 20mm distance. A 20mm
T-mount Extension Tube, available from many astronomy
retailers, will help you achieve the correct back focus distance. If
you require a more complex optical train for your CCD camera,
consult a trusted astronomy retailer.
For imaging, we recommend using T-system components
because threaded connections place your CCD camera or
digital SLR at the correct back focus distance for optimum
performance. Not only are they strong, but they also hold your
camera perfectly square to the light path.
To mount a high-performance video camera, add the T-Adapter
plus a T-to-C adapter. (Like the T-mount system, the C-mount
system is an industry standard. It uses 1×32 tpi threads with a
back-focus distance of17.5mm.)
For consumer video systems such as electronic eyepieces,
planetary cameras, and webcams that attach to the telescope
using a standard 1.25-inch eyepiece barrel, simply use the same
components that you use for visual observing. Just remove the
eyepiece from the telescope and replace it with the camera.
Many imaging programs allow you to shoot short exposures
through the telescope. On a solid, polar-aligned equatorial
mounting, you may be able to expose for 30 seconds or more.
With such exposure times, you can capture wonderful images of
the Moon, planets, eclipses, bright star clusters, and objects like
the Orion Nebula.
However, for long exposures on deep-sky objects, you will need
to guide the telescope. The days of guiding by eye are over;
electronic auto-guiders are the new standard. A functional and
relatively inexpensive autoguiding setup consists of a small
refractor mounted piggyback on your EdgeHD telescope. You
will need a dovetail bar attached to the EdgeHD tube. Celestron
offers an 80mm guide telescope package (item #52309) to
be used with the NexGuide Autoguider (item #93713). For
sub-exposures exceeding 10 minutes or so, piggybacked guide
telescopes potentially suffer from differential flexure; for such
imaging, consider the Off-Axis Guider (item #93648).
The Celestron EdgeHD 13
Celestron's EdgeHD: The Versatile Imaging Platform
5.25 inches
133.35±0.5 mm
Small T-Adapter
Camera Adapter
Digital SLR
Reducing Ring
Small T-Adapter
T-to-1.25” Adapter
Large T-Adapter
T-Ring Adapter
Digital SLR
925, 1100,
and 1400
5.75 inches
146.05±0.5 mm
Large T-Adapter
T-to-C Adapter
Astro Video Camera
Large T-Adapter
T-system Spacer
CCD Camera
FIGURE 14. It is easy to position your digital SLR camera, an astronomical CCD camera, a high-performance video camera, or an
inexpensive webcam at the focus plane of your EdgeHD telescope. For the sharpest wide-field imaging, your goal is to place the
sensor 5.25 inches behind the rear flange of the EdgeHD 800, or 5.75 inches behind the rear flange of the EdgeHD 925, 1100,
For those who wish to make images with a faster focal ratio
than EdgeHD 1100’s ƒ/10 or the EdgeHD 1400’s ƒ/11, we
designed a five-element 0.7× reducer lens for each of these
EdgeHD telescopes. (For more information, see Appendix B.)
The Reducer Lens 0.7× for the EdgeHD 1100 is item #94241;
for the 14-inch, item #94240. (The newly-released EdgeHD
800 Focal Reducer is item #94242.)
The reducer lens attaches directly to the 3.290×16 tpi threaded
baffle tube lock nut on the back of the telescope. Since the back
focus distance for the 1100 and 1400 reducer lens is 5.75 inches
(146.05mm), you can use the same T-Adapter and camera
T-Ring you would use for imaging at the ƒ/10 or ƒ/11 focus. The
linear field of view is still 42mm diameter, but the angular field is
43% larger, and exposure times drop by a factor of two.
For super-fast, super-wide imaging, the EdgeHD telescope
series supports Starizona’s Hyperstar lens. Mounted on the
corrector plate in place of the secondary mirror, the Hyperstar
provides an ƒ/1.9 focal ratio on the EdgeHD 1400, and ƒ/2.0 or
ƒ/2.1 on the 800, 925, and 1100. Covering a 27mm diameter
field of view, the Hyperstar is a perfect match for APS-C format
digital SLR cameras. Because of the short focal length and
fast focal ratio, sub-exposures are just a minutes. With a solid,
polar-aligned equatorial mount, guiding seldom necessary.
14 I The Celestron EdgeHD
Of course, the focal length of any EdgeHD telescope can be
extended using a Barlow lens such as the Celestron 2x X-Cel
LX (item #93529) or 3x X-Cel LX (item #93428). Using a
Barlow, imagers can reach the desirable f/22 to f/32 range for
ultra-high-resolution lunar and planetary imaging.
In summary, the Celestron EdgeHD telescopes provide a flexible
platform for imaging. You can work at the normal ƒ/10 or ƒ/11
Cassegrain focus for seeing-limited deep-sky images or add
the reducer lens for wider fields and shorter exposure times.
With a Hyperstar, you can grab wide-field, deep-sky images
in mere minutes. And finally, you can extend the focus to capture
fine lunar and planetary images with a quality Barlow lens.
When you buy an EdgeHD telescope, you’re getting an imaging
platform that covers all the bases, from fast, wide-field imaging to
high-resolution imaging of the moon and planets.
The classic Schmidt-Cassegrain telescope introduced tens of
thousands of observers and imagers to astronomy and nurtured
their appreciation for the wonder of the night sky. Today, observers
and imagers want a more capable telescope, a telescope that
provides sharp close-ups as well as high-quality images all the
way across a wide, flat field of view. But, consumers want this
advanced optical technology at an affordable price.
Celestron has designed the EdgeHD to meet customers’ needs.
The EdgeHD is not only coma-free, but it also provides a flat
field so that stars are sharp to the very edge of the field of view.
In this brief technical white paper, we have shown you the inner
workings of our new design. We also demonstrated the care we
exert as we build and test each EdgeHD telescope. We trust that
we have proven that an EdgeHD is the right telescope for you.
You may find the following resources to be useful in
learning about optical design, fabrication, and testing:
DeVany, Arthur S., Master Optical Techniques. John Wiley
and Sons, New York, 1981.
Fischer, Robert E.; Biljana Tadic-Galeb; and Paul R. Yoder,
Optical System Design. McGraw Hill, New York, 2008.
Geary, Joseph M., Introduction to Lens Design.
Willmann-Bell, Richmond, 2002.
Malacara, Daniel, ed., Optical Shop Testing. John Wiley
and Sons, New York, 1978.
Rutten, Harrie, and Martin van Venrooij, Telescope Optics:
A Comprehensive Manual for Amateur Astronomers.
Willmann-Bell, Richmond, 1999.
Smith, Gregory Hallock, Practical Computer-Aided Lens Design.
Willmann-Bell, Richmond, 1998.
Smith, Gregory Hallock; Roger Ceragioli; Richard Berry,
Telescopes, Eyepieces, and Astrographs: Design, Analysis, and
Performance of Modern Astronomical Optics. Willmann-Bell,
Richmond, 2012.
Wikipedia. Search references to specific topics.
See: http://en.wikipedia.org/wiki/Optical_lens_design
and many associated links.
Wikipedia. Search references to T-mount.
See: http://en.wikipedia.org/wiki/T-mount and associated
camera system links.
Wilson, R. N., Reflecting Telescope Optics I and II.
Springer-Verlag, Berlin, 1996.
ZEMAX® Optical Design Program, User’s Guide.
Radiant Zemax LLC, Tucson, 2012.
The Celestron EdgeHD 15
Appendix A:
Technical Profiles of EdgeHD Telescopes
When evaluating astronomical telescopes, astroimagers must
bear in mind the many factors that influence image quality. The
major factors at play are:
Airy Disk and Seeing Blurs
• The sampling by pixels of the image sensor
• The diffraction pattern of the telescope
• The image formed by the telescope
To aid astroimagers, this Appendix presents a spot matrix plot
for each of the telescopes in the EdgeHD series. To determine
the size of the images that you observe in your exposures, these
must be compounded with the other factors that affect your images.
In the spot matrix plots we have provided, each large gray box
is 64μm on a side, and consists of a ten small boxes 6.4μm
representing a pixel in a “typical” modern CCD camera. The
black circle represents the diameter of the Airy disk to the first
dark ring. It is immediately clear that for each of the EdgeHDs,
two 6.4μm pixels roughly match the diameter of the Airy disk.
This means that under ideal conditions, a CCD camera with
pixels of this size will capture most of the detail present in the
telescopic image. Referring to Figure A1, the left column shows
the Airy disk for a telescope with a central obstruction of 34%.
Because the light in the Airy disk is concentrated into a smaller
area in the center, capturing all of the image detail in a planetary
or lunar image requires using a 2x or 3x Barlow lens to further
enlarge the Airy disk.
Unfortunately, ideal conditions are fleeting. During a typical CCD
exposure, atmospheric turbulence enlarges the image of all
stars, and furthermore, it causes the images to wander. On the
steadiest nights, the “seeing” effect may be as small as 1 arcsecond.
In Figure A1, the “superb seeing” column shows blurs with a
FWHM (full-width half-maximum) of 1 arcsecond. The next column
shows excellent seeing (1.5”), and the right column shows 2”
seeing blurs, typical of many nights at most observing sites. It
is important to note that as the focal length of the telescope
increases, the diameter of the seeing blur increases in proportion.
With a small telescope, seeing plays a smaller role. With the large
apertures and long focal lengths of the EdgeHD series, nights of
good seeing become particularly valuable.
16 I The Celestron EdgeHD
• The guiding accuracy during exposure
• The “seeing” quality during exposure
FIGURE A1. Shown at the same scale as the matrix spot
diagrams are the Airy disk and the point-spread-function
of seeing disks for average (2.0”), excellent (1.5”), and superb
(1.0”) seeing.
Celestron EdgeHD 800
On-axis, the spots show that the 8-inch EdgeHD is diffractionlimited in both green (for visual observing) and red (for imaging).
And because blue rays are strongly concentrated inside the
Airy disk, the 8-inch EdgeHD is diffraction-limited in blue light.
Off-axis, its images remain diffraction-limited over a field larger
than the full Moon.
For an imager using an APS-C digital SLR camera, relative
illumination falls to 84% at the extreme corners of the image.
Although for bright subjects this minor falloff would pass
unnoticed, for imaging faint objects we recommend making and
applying flat-field images for the best results. For CCD imaging,
we always recommend making flat field images.
Portability and affordability are the hallmarks of the EdgeHD
800. Although the 8-inch covers a 42mm image circle, we
optimized its optics for the central 28mm area, the size of an
APS-C chip in many popular digital SLR cameras.
The Celestron EdgeHD 17
EdgeHD 925
The spot matrix shows that on-axis images are diffraction
limited at all three wavelengths, and remain diffraction-limited
over the central 15mm. While blue and red are slightly enlarged,
in green light images are fully diffraction-limited over a 38mm
image circle. The size of the off-axis blue and red spots remain
nicely balanced.
On a night of average seeing, stars will display a FWHM of
23μm, comparable in size to the spot pattern at the very edge
18 I The Celestron EdgeHD
of a 42mm field. Relative illumination in the EdgeHD 925 is
excellent. The central 12mm is completely free of vignetting,
while field edges receive 90% relative illumination. For most
imaging applications, flat fielding would be optional.
For full-field imaging on a tight budget, the EdgeHD 925 is an
excellent choice. It offers nearperfect on-axis performance and
outstanding images over a full 42mm image circle.
Celestron EdgeHD 1100
The 11-inch EdgeHD is optimized to produce its sharpest
images in green and red; at these wavelengths it is diffractionlimited over roughly two-thirds of the full 42mm image circle.
The relative illumination remains 100% across the central
16mm, then falls slowly to 83% at the very edge of a 42mm
image circle.
For pictorial images with an APS-C digital SLR camera, flats are
unnecessary. For monochrome imaging with an astronomical
CCD camera, we always recommend making flat-field images.
On nights when the seeing achieves 1.5 arcseconds FWHM,
star images shrink to 18μm at the focal plane. On such nights,
the EdgeHD 1100 delivers fine images over a 30mm image
circle, and well-defined stars over the full 42mm field.
The EdgeHD 1100 is a serious telescope. Its long focal length
and large image scale give it the ability to capture stunning
wide-field images of deep-sky objects with a large-format
CCD camera.
The Celestron EdgeHD 19
Celestron EdgeHD 1400
In the matrix spot diagrams, note the tight cluster of rays in
green light, and the well balanced spherochromatism in the
blue and red. These spots are far better than spots from a fine
apochromatic refractor of the same aperture.
In green light, the EdgeHD 1400 is diffraction-limited over a
28mm image circle, although atmospheric seeing enables it
to display its full resolution only on the finest nights. Relative
illumination is 100% across the central 16mm, and falls
slowly to 83% in the extreme corners of a full-frame 35mm
20 I The Celestron EdgeHD
image sensor. We have seen excellent results when the
14-inch EdgeHD is used with a KAF-16803 CCD camera over
a 50mm circle.
The EdgeHD 1400 is a massive telescope, well suited to
a backyard observatory or well-planned away-from-home
expeditions. Its long focal length and large image scale offer
skilled imagers the opportunity to make images not possible
with smaller, less capable telescopes.
Appendix B:
Perhaps the most useful accessory you can get for an EdgeHD
telescope is a focal reducer. Although the long focal length
is a great advantage in capturing detailed images of nebulae,
galaxies, and especially of planetary nebulae, it also means the
field of view is sometimes smaller than desirable. The relatively
slow focal ratio also means rather long exposure times. We
designed our 0.7× Focal Reducer to provide a field of view
1.4× larger in angular diameter, giving you twice the sky area
coverage and halving the exposure time required to reach a
given signal-to-noise ratio. If your passion is imaging large
deep-sky objects, imaging in Hα, SII, and OIII narrowband,
capturing the faint reflection nebulae often found around
Barnard’s dark objects, or just cutting your exposure (and
guiding) times down, the focal reducer is a “must-have” item.
Back in the days of film astrophotography, focal reducers
came to be poorly regarded. Although they would shorten the
focal length, they also produced fuzzy star images, had bad
field curvature, and suffered from severe vignetting. But the
days of film and ersatz focal reducers are over. The modern
EdgeHD focal reducer is the product of optical engineering
and precision manufacturing on a par with the design and
production of wide- and ultra-wide-field eyepieces.
The EdgeHD 0.7× Focal Reducer
FIGURE B1. The EdgeHD 0.7x Focal Reducer shortens the
focal ratio of the of the EdgeHD 1400, 1100 and 800 while
maintaining sharp images across the full field. This enables CCD
imagers to reach the same signal-to-noise ratio on extended
objects in half the exposure time, and brings even the faintest
deep-sky objects within the range of your high-end digital SLR
We designed three EdgeHD 0.7x focal reducers, each
specifically tailored to the EdgeHD 1400, 1100, and 800,
respectively. The 1400 and 1100 reducers contain five
precision optical elements, while the 800 contains four
elements. To attain a level of performance worthy of the
EdgeHD, the designs employ low-dispersion lanthanum
rare-earth glass to control both chromatic and geometric
aberrations. All optical surfaces are multi-layer anti-reflection
coated to maximize light transmission, provide high-contrast
images, and minimize image ghosting.
The matrix spot diagram shows that star images on-axis are
diffraction-limited in green light, while rays at all wavelengths
concentrated near the Airy disk. Even at the outer edge of the
42mm image circle, green and blue rays are clustered tightly,
while red shows only a weak flare.
Both physically and mechanically, the 0.7× Reducer Lens is
more than comparable to a top-of-the-line wide-field eyepiece.
The CNC-machined housing easily supports the full weight
of your CCD camera or digital SLR camera without sag or
movement. And for safe storage, each unit is provided with
threaded metal covers for both the front and the back.
The Celestron EdgeHD 21
Celestron EdgeHD 0.7× Reducer
Large T-Adapter
T-Ring Adapter
Digital SLR
1100 and
5.75 inches
146.05±0.5 mm
0.7× Reducer
Large T-Adapter
T-system Spacer
CCD Camera
The matrix spot diagrams show that the bulk of rays cluster
tightly in or near the Airy disk, with a diffuse scatter most strongly
seen in the red light. Plotted at the same scale as those for the
EdgeHD, the spots demonstrate that the focal reducer’s star
images are even smaller than those of the telescopes.
22 I The Celestron EdgeHD
For observers who wish to pursue faint nebulae in RGB or in
narrowband, the 0.7× Focal Reducer is a valuable accessory that
halves the necessary exposure time with no sacrifice in resolution
or image quality.
Image by André Paquette
Imagine the thrill of seeing the first images from your Celestron
EdgeHD! A quick glance at the whole image shows that you have
captured your target’s faint outer extensions. Across the field, from
one side to the other, star images are sharp, crisp, and round. As you
process your image, fine details in the target object reveal themselves.
Star clouds, delicate dust lanes, subtle HII regions—it’s all there, credit
to your skill and the design of your EdgeHD telescope. The image
shown here is a single monochrome 10-minute exposure taken with
an Apogee U16 camera (KAF-16803 CCD chip) and a Celestron
EdgeHD 1400 telescope on a CGE Pro mount.
The Celestron EdgeHD 23
The Celestron EdgeHD • ©2013 by Celestron • All rights reserved.
Torrance, CA 90503 U.S.A. • www.celestron.com
Combining Celestron’s newly designed dual fork arm
computerized mount with its award winning EdgeHD
optical system, the NEW CPC Deluxe HD Series
offers you a high definition experience!
80 mm Guidescope Package
CPC Deluxe 1100 HD
NexGuide Autoguider
Nightscape CCD Camera
HD Pro Wedge Mount
Accessorize your CPC Deluxe HD
to create the ultimate telescope
for astro imaging
+ Nightscape One shot color imaging camera
with 10.7MP CCD sensor, mechanical shutter,
TEC cooling and processing software.
+ HD Pro Wedge Provides a stable platform
essential for polar aligning your fork arm
telescope for smooth tracking all the way
across the meridian.
+ 80 mm Guidescope Package 600 mm focal
length guidescope and ring package for
piggyback guiding during astro imaging.
All featured accessories sold separately
+ NexGuide Autoguider NexGuide stand-alone
autoguider eliminates the need for a laptop
computer for guiding during long-exposure
CPC Deluxe 800 HD
CPC Deluxe 925 HD
CPC Deluxe 1100 HD
The wait is over! Celestron’s award winning EdgeHD optical system is now available on a newly designed
top-of-the-line dual fork arm computerized mount – The CPC Deluxe HD. Available in 8”, 9.25” and 11” models,
the CPC Deluxe HD telescope line re-defines everything that amateur astronomers are looking for –ease of use,
quick and simple GPS alignment, improved ergonomics, enhanced computerization, unsurpassed optical quality
and most importantly, affordability. As a visual instrument, the EdgeHD optical system delivers pinpoint images
across your widest field eyepiece, providing you stunning clarity and sharpness that will leave you wanting more.
When used for astro imaging with our new Nightscape or your own favorite CCD or DSLR camera, the
EdgeHD optical system produces a flat focal plane allowing pinpoint stars to the very edge of your image.
Own this premier telescope line today, and it will surely keep you up all night.
Starbright XLT Coatings
Internal GPS
Computerized Flash Upgradeable Hand Control
with SkyAlign™ Alignment Technology
40,000+ Object Database
Fastar Versatility
NexRemote Telescope Control Software
All-Star™ Polar Alignment
Improved Gear System for Smoother Tracking
Permanent Periodic Error Correction
CPC DELUXE 800 HD 11007
2032 mm (f/10) 40 mm Plössl - 1.25¨ (51x)
50 mm
CPC DELUXE 925 HD 11008
2350 mm (f/10) 23 mm Luminos - 2¨ (102x) 50 mm
CPC DELUXE 1100 HD 11009
2800 mm (f/10) 23 mm Luminos - 2¨ (122x) 50 mm
For complete specifications and product information visit


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