CAUTION!
X
NEVER ATTEMPT TO LOOK AT THE SUN WITH
YOUR APERTURA™ DOBSONIAN TELESCOPE
UNLESS YOU HAVE A FULL-APERTURE
SOLAR FILTER (NOT INCLUDED WITH
TELESCOPE) INSTALLED OVER THE OPEN END OF
THE OPTICAL TUBE. NEVER USE AN EYEPIECEMOUNTED SOLAR-FILTER ALONE AND ALWAYS
COVER THE FINDERSCOPE EYEPIECE WITH A
PLASTIC DUST CAP. WITHOUT A FULLAPERTURE SOLAR FILTER INSTALLED, YOU RISK
SEVERE EYE DAMAGE AND PERMANENT
BLINDNESS!
Please take a few minutes to read over the
assembly instructions to familiarize yourself
with the individual parts and procedures
before attempting to assemble your
Apertura™ Dobsonian Telescope.
Before using your Apertura™ Dobsonian
Telescope, please review and follow the
“Procedure for collimation” section of this
manual. You must properly collimate your
telescope to achieve optimal viewing
through this quality optical instrument.
DOBSONIAN
TELESCOPE
Assembly Instructions and User’s Guide
Unpacking your Apertura™ Dobsonian Telescope
Parts list:
Optical Tube Box (package 1 of 2)
Dobsonian optical tube
8x50 90-degree right-angle finderscope
Plastic tube cover
Laser collimator
2 silver side bearings
Fan power pack (batteries not included)
Eyepieces:
30 mm (2” format)
9 mm (1.25” format)
2”-to-1.25” eyepiece adapter
35mm Extension Tube
Moon filter (1.25” format)
Base Mount Box
Wood components:
1 small panel – front
1 large panel – right
1 large panel – left
2 large round base plates
Turntable hardware:
1 round plastic roller-bearing disc
2 metal discs
1 Four-hole eyepiece tray
1 handle
3 black plastic feet
1 Allen wrench
(package 2 of 2)
1 adjustment knob assembly:
1 bolt with knob head
1 large washer
1 small bearing washer
1 small washer
1 axle sleeve
10 long black Allen screws
(only 8 screws for the AD8 model)
2 medium silver Allen screws
3 medium Phillips screws
2 short black Phillips screws
Assembling the DOBSONIAN BASE HOUSING
Attach handle to the BASE FRONT with
two medium silver Allen screws. The
curved edge of the board is the top of
this part when vertical.
! IMPORTANT ! Make sure the flat face
of the embedded T-nuts are on the BACK
side of the board (opposite the handle).
Attach BASE RIGHT to BASE FRONT
with two long black Allen screws.
(The BASE RIGHT is the one with
two smaller pre-drilled holes for
the eyepiece tray)
Attach BASE LEFT to BASE FRONT
with two long black Allen screws.
Be sure all three sides are secure.
BACK
Locate the BOTTOM BASE PLATE.
The BOTTOM BASE PLATE has
3 holes around its edge and a
brass fitting in the center hole.
Attach the 3 feet to the BOTTOM
BASE PLATE’s bottom side with 3
medium Phillips screws, with the
wider side of the feet facing the
board.
(The bottom side of this plate has
the brass fitting almost flush with
the surface – see inset picture)
Locate the TOP BASE PLATE.
The TOP BASE PLATE has
several holes around its edge
(not counting center hole).
Model AD8 = 4 holes
Model AD10, AD12 = 6 holes
Turn the completed BASE
HOUSING upside down.
Align the holes of the UPPER
BASE PLATE with the
holes of the BASE HOUSING.
Screw long black Allen screws through
the BOTTOM BASE into the BASE
HOUSING making sure the side with
the recessed holes is facing away from
the BASE HOUSING.
Place BOTTOM BASE PLATE with
feet facing down.
Insert AXLE SLEEVE into the Center
hole.
ROLLER BEARING ASSEMBLY
Place one of the two METAL DISCS
on the BOTTOM BASE PLATE aligning the
AXLE SLEEVE to hole in the Center.
(It can be flipped either way)
Now place the ROUND PLASTIC
ROLLER-BEARING DISC over the first
METAL DISC.
(It can be flipped either way)
Follow this with placing the
second METAL DISC over the
ROLLER-BEARING DISC.
(It can be flipped either way)
Pick up the BASE HOUSING
with UPPER BASE PLATE
already attached and place it
onto the AXLE SLEEVE of the
BOTTOM BASE PLATE.
Assemble washers onto the
ADJUSTMENT BOLT in this order:
Small washer
Ball bearing washer
Larger washer
Thread the ADJUSTMENT BOLT
through all of the assembled base
parts. Tighten the knob until it feels
firm but not too tight.
TIP: Tightening or loosening this
knob is how you will adjust the
amount of effort it takes to rotate
your Apertura™ Dobsonian
telescope on its base.
Attach the 4-HOLE EYEPIECE TRAY
to the BASE RIGHT panel of the
BASE HOUSING ASSEMBLY using
the two pre-drilled holes and two
small black Phillips screws.
Assembling the OPTICAL TUBE
Remove (2) bolts located on each
side of the OPTICAL TUBE
Align SILVER SIDE BEARING ASSEMBLY
with the same holes and insert the top
bolt first (do NOT tighten yet). Then slide
the BEARING ASSEMBLY up if necessary
and insert the bottom bolt.
Repeat on the other side of the
OPTICAL TUBE.
The position of these BEARING
ASSEMBLIES will determine the balance
point of your telescope and may need to
be adjusted depending on what
accessories are installed on your optical
tube.
With the included accessories attached
to the Apertura Dobsonian Telescope,
balance is achieved with these initial
settings (see pictures).
AD8
NOTE: When other accessories are attached
to the OTA, the balance point may change and
appropriate adjustments to this these settings
may be required.
Move the OPTICAL TUBE over onto
the BASE HOUSING assembly.
TIP: The metal seam of the telescope
tube should be turned to the side of
the base that has the handle (BASE
FRONT).
TIP: The flat sides of the SILVER SIDE
BEARING ASSEMBLIES should be facing
up (flat).
TIP: Tightening or loosening the black,
plastic knobs of the side bearing
assemblies is how you will adjust the
tension of the bearings. If excessive
tension is required to balance the
telescope (e.g. because of heavier
eyepieces/accessories), then you may
need to adjust the balance point of the
bearing assemblies as described in
Step 2 above.
AD10 & AD12
Locate the 90-DEGREE RIGHTANGLE FINDERSCOPE and attach
it to the dovetail finderscope
bracket on the side of the
OPTICAL TUBE.
Use the thumbscrew to tighten
the finderscope into place.
Aligning Your Finderscope
When first attached, the finderscope will not be perfectly aligned with the telescope’s optics. Once the
finderscope is properly aligned with the main telescope’s view, the finderscope’s extra-wide field of view will
help you easily center the main telescope on objects you wish to view.
Start by inserting the large 30mm eyepiece into the telescope’s focuser. Point the telescope at a large,
distant and stationary object (such as the detail on a billboard at least 250 yards away). Focus the eyepiece and
center that distant object in the eyepiece; in other words, start with an earthbound object for focusing and
alignment. If you are not able to achieve good focus, you may need to insert the included 35mm Extension Tube
into the focuser and then insert the 30mm eyepiece into the extension tube. The 35mm Extension Tube is used
with low-power eyepieces to extend the focal length, making it possible to focus at low magnification.
Now look through the finderscope. To focus the finderscope, first loosen the lens cell by unscrewing it a
half-turn. Then turn the locking ring the other way, to pull it back from the lens cell and expose the maximum
number of threads on the finderscope body. Turn the lens back and forth to focus your view. Once the lens is
focused, then tighten the locking ring to hold the lens cell in place. You may need to make a slight focus
adjustment the first time you use the finderscope on the night sky, but once the focus is set on the sky you
should not need to adjust it again.
Finderscope Locking Ring
Finderscope Lens Cell
Once focused, then align your finderscope by gently
adjusting the two thumbscrews on the finderscope bracket (the silver “knob” contains a spring that gives backpressure to the thumbscrews and does not need adjustment). Carefully align the finderscope body until its
crosshairs are centered on the object that is currently centered in the main telescope’s eyepiece.
Alignment Screws
(black Nylon)
Spring Tensioner
(no adjustment)
If you bump the finderscope during transport or use and disturb its alignment, it will only require a quick and
easy adjustment of the two thumbscrews to realign the finderscope to the main telescope’s view.
10:1 Precision Micro Crayford Style Focuser
Your Apertura Dobsonian Telescope comes standard with a Dual-Speed 10:1 focuser. It is
pictured here with the drawtube fully extended.
Focuser Drawtube
extended
Brass Compression Ring
Compression
Adjustment Screws
Tensioning Screw
Full speed
adjustment wheel
Locking Screw
1/10 speed
adjustment wheel
The scale on top shows the
The Apertura focuser will
focuser drawtube fully extended
accept 2“ and 1.25” eyepieces
to 4cm or 1.5”. !! IMPORTANT !!
(with included adapter) and
Locking screw (under tensioning
other common hardware. The screw) must be backed out to
amount of extension required allow full drawtube travel.
for each eyepiece will vary,
therefore retract or extend the drawtube to bring the image
into focus. For lower power, wide field-of-view (FOV)
eyepieces, it may be necessary to increase the focal length by fitting the 35mm Extension
Tube into the focuser as an adapter to achieve focus.
The movement of the focuser tube is a result of tension inside the focuser which can be
adjusted by the tensioning screw. In general, use the lightest amount of tension that will
work with the installed components for smooth action. But as heavier eyepieces are used,
especially in conjunction with other components, increase the tension to compensate for
the extra weight.
Once you achieve focus, you may want to use the locking screw to hold the focuser in place
even if the adjustment wheels are moved. This is helpful when exchanging parfocal
eyepieces or having other viewers come to the eyepiece.
Eyepiece Selection
Your Apertura™ Dobsonian Telescope comes standard with two eyepieces: a 2”
diameter wide field, low-power eyepiece with a 30mm focal length and a 1.25”
diameter high-power eyepiece with a 9mm focal length. To get the best results from
your telescope, always start with your widest field (lowest power) eyepiece, then work
your way up to the higher power eyepiece, keeping the image centered throughout.
35mm Extension Tube: This is used with low-power eyepieces to extend the focal
length, making it possible to focus at low magnification. The 35mm Extension Tube fits
into the 2” opening of the focuser and then accepts 2” eyepieces, or 1.25” eyepieces
with the 1.25” adapter installed.
Deep-sky objects are best observed with medium magnification due to their dimness at
higher magnifications. Astronomical points of interest within our solar system are good
candidates for higher magnification because they are generally brighter than deep sky
objects. Of course, experimentation is always the most rewarding approach to
determining eyepiece selection.
Observation Tips
Your telescope will perform best when local artificial lighting is kept to a minimum.
Nearby streetlights and lighted buildings cause a lot of light pollution and will degrade
the quality of your view with your telescope.
When choosing a viewing location, try to find a spot far away from tall structures with a
wide view of the open sky.
Allow your eyes time to adjust to the darkness before you expect to see any faint
objects of the night sky. Usually 30 minutes is long enough for your eyes to totally adapt
to the dark. Preserve your dark-adapted vision by avoiding looking at sources of light
(street lights, cell phones, computers, etc.). If you are exposed to a light source, the
adjustment period will begin again. After your eyes have reached their dark-adapted
state you’ll want to consider using a red-lens light source for activity in the dark.
Acclimating Your Telescope
Before using your telescope, you should allow its temperature to equalize to that of the
ambient outside air temperature outside. Larger scopes take longer to equalize and
should be given half- to one-full hour depending on the temperature difference (one
hour for a difference of 40 degrees Fahrenheit). Keeping your telescope and optics in an
outside or non-environmentally controlled building such as a garage or shed can
decrease the time it takes for the temperature differential to stabilize. To aid in
equalizing the temperature of your Apertura™ Dobsonian Telescope, plug in the
onboard fan. The fan pulls in outside air to more quickly stabilize the internal
temperature of the scope, especially the large primary mirror.
Viewing Conditions
The quality of the conditions for viewing are referred to as “seeing,” usually rated on a
scale of 1 to 10, with 10 as perfect seeing and 1 as very poor. There are two major
conditions to notice in evaluating viewing conditions on any given night: atmospheric
disturbance and air transparency. The best conditions for astronomical viewing are
when atmospheric disturbances are at a minimum. Lower your expectations when
trying to use your scope too early in the night or trying to focus on objects close to the
horizon as this will impair your ability to view clearly. Generally, you want to set your
telescope up on the highest point possible as it affords the highest quality viewing and
isn’t as subject to atmospheric disturbances. A good way to determine how well you will
be able to see on any given night is to look at bright stars about 40 degrees above the
horizon and look for twinkling of stars. Twinkling is caused by atmospheric disturbances
and is an indicator that quality viewing may be difficult. Though, often what twinkles
near the horizon will become steadier later in the evening as it moves higher in the night
sky.
Also affecting the viewing quality is the transparency (clarity) of the air. Remember that
our viewing of the universe from the ground begins by looking through many miles of air
that is full of particles and water which is in constant motion and changes regularly.
Tracking Celestial Objects
Since the Earth is always rotating, astronomical objects will appear to move across the
night sky. When using your Apertura™ Dobsonian Telescope for a little while, you need
to manually track the observed objects by carefully moving the scope’s tube to keep the
object relatively centered in the eyepiece. Using higher magnification means that you
have to make more frequent tracking adjustments than when using lower magnification.
A popular method for locating night sky objects is called “star-hopping.” Start by finding
a known star or moon or planet, and scan from there to other stars closer to the
destination object. This method is far from new but it might take a little time to master
requiring at least a rudimentary familiarity with the location of a variety of celestial
objects. However, learning to star-hop makes object location much quicker and gets
you to where you want to be without much fuss. Experience will make this easier and
dramatically increase your personal knowledge of the night sky! You don’t need to
memorize every single object in the night sky, but it can be very rewarding just knowing
a handful of the most prominent sights such as the Orion constellation, the Big Dipper,
the North Star, etc.
A star chart will help you determine which constellation your target object is near. Find
the brightest star in that constellation and place it in the center of your eyepiece. Again
refer back to your star chart to figure out the next brightest star as you gradually move
towards your intended target. If you are unsuccessful at first, please be patient and
repeat the steps until your final destination is in view. Again, your speed will increase
with experience.
Procedure for collimation
CAUTION: Do NOT allow the laser to shine in your eye (either directly or indirectly off
the telescope’s mirrors) as that may damage your eye permanently.
1. Remove any eyepiece from the focuser.
2. Look into the focuser and confirm that you see the secondary mirror centered in
the hole. Reflected in the secondary mirror, you should be able to see the primary
mirror and the three small clips around the edge of the primary mirror. If not, you
will need to rotate the secondary mirror assembly with your hand (be careful not
to TOUCH the reflective surface of the secondary mirror itself) until the reflection
of the primary mirror is centered in the secondary mirror. In addition, although
the shape of the secondary mirror is actually oval, when properly aligned it will
appear to be circular as viewed through the focuser.
3. Insert the laser collimator into the 2” adapter sleeve and then insert that into the
focuser. Secure the laser collimator with the thumbscrew. Turn on the laser
collimator and rotate its target face toward the back end of the scope (the
primary mirror end).
4. Hold up a piece of paper in front of the telescope to see if the laser is missing the
secondary mirror on reflection. If the laser isn’t reflected onto the paper, then
most likely it is hitting the secondary mirror as it should.
5. Carefully peer into the tube to see where the laser is hitting the primary mirror
below. CAUTION: Do NOT allow the laser to shine directly into your eye from the
telescope’s mirrors. The laser should be shining in the middle of the small donut
ring in the middle of the primary mirror. If it is not, adjust the tilt of the secondary
mirror using the three small screws on the top of the secondary mirror assembly
until the laser is centered in the donut ring on the primary.
6. Now view the target face on the laser collimator to see if the laser is hitting
anywhere on the target face. If not, then this simply means that the primary
mirror is far enough out of adjustment that the laser is outside the target
face on the collimator. In either case, you will need to move to the bottom end of
the scope and loosen the large white locking knobs. Then adjust the angle of the
primary mirror with the large black adjustment knobs until the laser becomes
centered in the hole in the middle of the laser collimator’s target face.
7. Once accomplished, lock the primary mirror assembly with the white knobs. This
may cause some minor movement of the mirror, so continue fine adjustments
until all six knobs are firm and the laser is centered on its target.
Keeping your telescope clean
Do not touch, rub, brush, wipe or otherwise contact the primary mirror or secondary
mirror. Over time a thin layer of dust will accumulate on the surface of these mirrors.
This is normal and is best left alone. If it is absolutely necessary, use only an optical lens
brush and lens bulb puffer to remove dust from your mirrors.
The outside of your Apertura™ Dobsonian Telescope is easily cleaned with a dust cloth
or sponge for fingerprints, dust, etc.
Clean other components ONLY when absolutely necessary and then ONLY with a mild
soap solution and lint-free cloth by gently blotting. Do not use any harsh cleaning
chemicals to avoid damaging the finish on your telescope and components.
Use a dry soft cloth to remove condensation from the outside of you telescope before
storing it. Do not try to dry the eyepiece or finderscope lenses but rather let them dry
naturally.
Avoid leaving your telescope in an excessively hot environment such as the inside of a
car as high temperatures can damage your telescope in several ways.