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The Education Bureau and Ho Koon Nature Education cum Astronomical Centre
jointly present
Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And
Space Science" in the New Senior Secondary Physics Curriculum
A Course for Laboratory Technicians
Session 1
Content
1
Introduction
1
2
Planetarium softwares
2
3
Solar observation
10
4
Computerized telescopes
15
5
Buying telescopes
25
6
Telescope terminology
27
7
Deep sky objects
28
8
A whole-sky star map
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Introduction
In Chapter 2.3.2 Section VI, Astronomy and Space Science, of the C&A Guide for Senior Secondary
(CDC 2007), the Curriculum Development Council emphasises that:
Students should develop basic skills in astronomical observation. Observation can
capture students’ imagination and enhance their interest in understanding the mystery
of the universe. It also serves to develop their practical and scientific investigation
skills. Students may use the naked eye to observe the apparent motion of celestial
bodies in the sky, and use telescopes/binoculars to study the surface features of the
Moon, planets and deep sky objects. Simple application of imaging devices such as a
digital camera, webcam or charge-coupled device (CCD) is useful. Project-based
investigation may also enhance students’ involvement and interest.
The Education Bureau (EDB) and Ho Koon Nature Education cum Astronomical Centre (HKNEAC)
therefore, have managed to present a course especially designed for secondary school laboratory technicians.
With the completion of the course, participants should be able to understand how practical astronomical
activities can facilitate in aspects such as: learning and teaching in NSS physics, using a planetarium software
to enhance the teaching of the ‘Astronomy and Space Science’, operating computerized telescopes and
supporting teachers in conducting activities.
All softwares recommended to participating schools are freewares and therefore leave the school
management the freedom to allocate their tight budget wisely. HKNEAC will continue to support all
participants after the training events and to provide advisories on activities planning and purchase of
equipments. For information on current astronomical events and news, the HKNEAC web site
(http://www.hokoon.edu.hk/)
as
well
as
the
Hong
Kong
Astronomical
Society
web
forum
(http://forum.hkas.org.hk/) are highly recommended.
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Planetarium softwares
Objectives
The participants should be able to preconfigure a planetarium software to suit different teaching purposes,
such as:
1. Introducing the celestial coordinate system;
2. Displaying the sky at different geologic latitudes;
3. Displaying the diurnal motion of the celestial sphere at different latitudes;
4. Displaying the motion of the sun on the celestial sphere throughout the year.
A What is a planetarium software?
A planetarium software is not just an electronic star map. It is embedded with powerful features such as:
a. Simulating the sky of any place on earth;
b. Displaying very realistic star images;
c. Simulating the real time sky or any astronomical event of a specific date;
d. Realistically representing deep-sky objects with photographic images;
e. Driving 'goto' telescopes;
f.
Preconfiguring to show specific sky events through the use of scripts.
B Stellarium(v.0.10.4)user guide
1 Install Stellarium 0.10.4; (Free download at http://stellarium.org/ )
2 Start Stellarium from your desktop;
3 Move the cursor to the far left and the 'configuration / vertical tool-bar' will pop up. Move the
cursor to the bottom of the screen. The 'visual effect / horizontal tool-bar' will come into view;
4
There are two small buttons at the lower left-hand corner of the screen. They are used to switch the
tool-bars on or off:
the tool-bar is off;
the tool-bar is on;
the status bar cannot be switched off.
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The visual effect / horizontal tool-bar:
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The configuration / vertical tool-bar:
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Location
Date / Time
View
Search
Configuration
Help
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7 Basic configuration:
a Right click on the 'Location' icon to bring out the world map, choose Xianggang, China from the
right pull down menu. Remember to select 'Use as default' on the lower left before closing the
map;
b Select the 'View' icon to bring out the dialogue box. Select 'Sky'. Configure your settings. For
example if you would like to prepare a meteor shower show, you can click to select the hourly
rate. Refer to the picture below for further explanation:
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Select 'Markings' and refer to the picture below for explanation:
Select 'Landscape' and choose a landscape of your liking. If you do not like to see obstruction on
the horizon, choose 'Ocean'. Select 'Use this landscape as default' before you leave;
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c Select the 'Configuration' icon to bring out the configuration menu. Select 'Navigation', Choose
'System date and time'. In this way Stellarium will show the current sky every time it starts;
Select 'Tools' and refer to the picture below for explanation:
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d Open the 'Help' box and you will be shown a list of hot keys.
e You have finished the basic configurations. Now click on the 'Date / Time' icon. Enter the date and
time of your planned observation session and start using this programme;
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Click on the icons on the horizontal-bar one by one and find out their functions. These functions can
be toggled on or off;
Press and hold the left mouse key. Then move the cursor around and find out what happens. You can
also use the direction keys on your keyboard to achieve the same results;
Roll the wheel on your mouse and find out the effect you can make. You can also use PgUp and
PgDn on your keyboard to get the same functions;
Now move around to find the planet Mars. Click to select the planet and then press the space bar to
place it in the centre of the screen. Now zoom in and you can study the features on Mars;
Click the 'Search' icon on the vertical-bar. Type Saturn in the blank space to search. When the planet
is found, zoom in until you can see its ring. What do you find near the planet Saturn? Click  a few
times to increase the time rate. See what happens.
Exercise:
2
3
Job
Find the constellation
Cassiopeia.
Find the constellation Gemini.
Find the Moon.
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Find NGC1952.
1
Problem
What does its lined figure look like?
Answer
What is its constellation figure?
Is the moon above horizon at the current
time?
In which constellation is the moon?
Where is it (in which constellation)?
What does it look like?
It has another label. What is it?
What is its nickname?
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In the configuration box choose
'Tools' and select to use 'Disk
Viewport'. Now use 'Search' to
find the constellation Cancer.
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Zoom in until the FOV (on the status-bar)
reads approximately 6°(the same field as
most binoculars). What can you see at the
centre of the constellation?
C Scripts
1
A script file is made up of many command lines. When a script file is loaded, Stellarium will be able
to run a preconfigured sky show such as a solar eclipse or the movement of Mars among the stars.
Scripts are extremely useful teaching aids.
2
To run a script, open the 'Configuration' dialog and go to the 'Scripts' tab. A list of available scripts
will be displayed in the list box on the left side. When a script name is selected by clicking on it, details
about that script will be shown in the panel on the right side. To run the selected script, click the 
button.
3
To install a script, copy the script and any related files to <User Data Directory>/scripts/>
D Scripting
1
The 0.10.4 scripting engine is still under development.
2
The scripting engine in version 0.9.1 is fully enabled. You can download this version here:
http://sourceforge.net/projects/stellarium/files/
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You can find detailed description here: http://www.stellarium.org/wiki/index.php/Scripts
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E Activities for students
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Read out the celestial position of an object:
a Previous knowledge: equatorial and horizontal coordinate systems;
b Students are asked to find, from Stellarium, the equatorial and horizontal coordinates, for both
Hong Kong and Beijing, of Mercury during a certain eastern or western elongation (teacher give
hints on the date of the event);
c Students are required to tell the differences between the coordinates found for both sites;
d Students should be able to point out which site is better suited for observing the selected event.
The positions of the celestial poles and the celestial equator as seen from different latitudes:
a Previous knowledge: the celestial sphere;
b Teacher describes how the north celestial pole and the celestial equator would appear in the local
night sky;
c Students describe how the north celestial pole and the celestial equator would appear in places
further north or even at the North Pole;
d Students describe how the celestial pole and the celestial equator would appear in places south of
HK or even at the South Pole;
e Use Stellarium to illustrate.
3
Diurnal motion at different latitudes:
a Previous knowledge: The celestial and the diurnal motion;
b With the help of Stellarium, the teacher explains how the the stars would appear to rise or set in
HK when look in different directions;
c Students describe the diurnal motions at higher northern latitudes as well as at the N. Pole;
d Students describe the diurnal motions at places south of HK as well as at the S. Pole;
e Use Stellarium to illustrate.
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The yearly motion of the sun on the celestial sphere:
a Previous knowledge: How sunshine is related to the inclination of earth's axis and seasons;
b Teacher explains how the midday sun seems to alter in altitude from day to day;
c Students simulate,with Stellarium, sunshine at places like Beijing, N. Pole, Singapore and Sydney
and compare their seasonal changes.
5
Teachers can simulate astronomical events with Stellarium and capture the motion pictures, with
softwares such as Camstudio http://camstudio.org/(freeware), for teaching purposes.
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Solar Observation
Objectives
Participants are able to set up an astronomical telescope on their own. They are able to organize a solar
observation session.
1
Warning:
Even the smallest telescope can converge the light of the sun into an extremely bright and hot
image which could crack the eyepiece and lead to damaging the eye of the observer;
b. Eyepiece-end solar filters are not safe. Only before-the lens solar filters which block 99.9997% of
the sun's radiation are safe for solar observation. These filters are aluminium-coated glass or
mylar material;
c. Throughout the session, either cover up the front lens of the finder-scope firmly or simply
remove the finder from the telescope tube;
d. Always point the telescope away from the sun when no one is doing any observation with it;
e. Sunglasses are not meant for observing the sun but wearing them when you are not observing
helps to filter off harmful radiation (e.g. UV);
f. Warn your students before starting a solar observation session each time.
a.
The following page carries a first-hand account from someone who hurt his eye while looking at the
sun through a small telescope. http://mintaka.sdsu.edu/GF/vision/others.html#Bunker
Aiming your telescope at the sun
You must always remember to put a solar filter in front of the telescope lens before you observe or
photograph the sun. There are many ways to aim your telescope at the sun even without looking through it.
a. Place a sheet of white paper behind the telescope. Then point the telescope approximately at the sun.
You should be able to see the shadow of the telescope cast on the paper by the sun. Move the telescope
freely until the shadow is the smallest. Now your telescope is pointing at the sun;
2
b.
Remove the diagonal, the eyepiece and the solar filter from the telescope. Point the telescope
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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approximately at the sun. Place a sheet of white paper behind the telescope. Move the telescope freely
until a bright, circular image is seen on the paper. Lock both axis of the mount. Put the filter back first
and then the diagonal and eyepiece. You are ready to observe.
3
a.
The white-light sun
The projection method
This is the safest way to observe the sun and you do not need a filter to do this. Point the telescope at
the sun. Use a low power eyepiece to project the sun's image onto a piece of white paper. You may use
a diagonal to direct the projected image to a different position for comfortable viewing. Place the paper
about 10cm from the eyepiece. Turn the focusing knob until the sun's image is sharp and clear. You can
now move the paper either near to or away from the eyepiece to adjust the size of the image.
Caution: You should only use Huygens (H) or Ramsden (R) type eyepieces. These eyepieces consist of
simple lens components only and therefore withstand high temperature better.
b.
Direct observation / photography
It is important to bear in mind that SAFTY comes first when it comes to observing the sun. Always put
on a solar filter in front of the lens before you observe. Solar filters for observation are denser than
those manufactured for photography. So a photography grade filter is unsafe for direct observation.
When you observe, it is recommended to use a diagonal to bring the image to a comfortable viewing
position.
A DSLR is most suitable for photographing the sun. It is important that you have the appropriate
camera adaptor for your DSLR. A shutter release cable will help minimize camera vibration when you
trigger the shutter. A DSLR with live-view mode feature will make focusing much easier and more
effective. Shooting with eyepiece projection enables you to take close ups on sunspot groups. But this
requires a special camera adaptor which can hold an eyepiece in it.
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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Though web cams are widely used in planetary photography, most web cam sensors are too small for
full disk solar photography. You should also bear in mind that strong light may damage the sensor.
4
The appearance of the sun in other wavelengths
With the advancement of filter technology, observing the sun in Hα and CaK have become more
affordable to amateur astronomers.
The Hα, CaK and white-light sun compared.
© 2003 by Greg Piepol. Use with permission.
Hα Observation: The technique is to use a narrow-band pass filter to cut off all unwanted radiation from
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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the solar spectrum and leaving only the Hα line (wavelength=656nm) at the red end to pass through. This
would result in a much dimmer, red image that is rich in details. Prominences, filament and spicules which
are invisible in the white-light image all come into view.
The Hα sun.
© 2003 by Greg Piepol. Use with permission.
CaK Observation: Calcium makes up only 0.008% of the sun's mass. The K line is from calcium ions that
emit and absorb energy in the ultraviolet portion of the solar spectrum in a broad region centered at 393.3
nm (3933 Å). Using a CaK filter would show the outline of supergranulation cells of the chromosphere.
The Chromospheric Network is the most prominent feature in this wavelength.
The sun in CaK
© 2003 by Greg Piepol. Use with permission.
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Activities for students
a.
Employing either the projection or photographic method, record the evolution of a group sunspots on
the solar surface. Then estimate the rotational period of the sun. Note that it is important to mark the
cardinal points on all of the records.
Train the students and make it a long-term activity to observe the sun daily and keep a record of the
sunspot numbers. In time these records will enable students to understand more about the activities of
the sun.
b.
The following web page contains a good software and guide for this purpose.
http://www.petermeadows.com/html/software.html
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Computerized Telescopes
Objectives
Participants are able to set up a portable astronomical telescope and do some simple manipulation.
1 What is a computerized telescope?
A computerized telescope is able to slew to any object in the sky automatically and track it while making
small adjustments to compensate for polar misalignment. Computerized telescopes comes in two types:
(i) the GoTo telescope with star data base and tracking functions built in;
(ii) the software guided telescope (SGT) which is driven by a computer software. Most SGTs are GoTo
telescopes on their own. Most SGTs conform to the ASCOM standard. The ASCOM platform is a third
party open source software.
2 Initializing a telescope
For a computerized telescope to function properly it must be initialized each time it is set up.
(i)
Set up the telescope with its main accessories;
(ii)
Carry out the polar alignment procedure;
(iii) Set up the connection to the computer (for SGT only).
It is important to point the polar axis of an equatorial mounted telescope very close to the north celestial
pole (this step can be omitted for an alt-azimuth mounted telescope). Then use the two-star alignment
method to do the final adjustment. This should provide enough information for the telescope to correct the
alignment error while tracking or slewing.
3 No power supply?
(i)
If you are not far away from an AC outlet, use an electric extension unit to extend the power
supply to your telescope. However it is important to tape the power cables to the ground so that
no one will be tripped over while moving around in the dark;
(ii)
Make sure you have ample supply of dry batteries or have the rechargeable battery fully charged
in advance;
(iii) When the notebook is not in use, switch it off to save power.
4 Instructions
Important:
(i)
During daytime activities, always remember to install the solar filter before observation;
(ii)
Balance your equatorial mount telescope.
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Vixen SXD Mount (Star Book and Star Book-S are similar)
A
Polar alignment
1
2
3
4
5
6
7
8
9
10
Set up the telescope on an open ground where it is flat and with a view of the Pole star;
Point the polar axis at Polaris;
Power on the telescope and then the Star Book. Enter Scope Mode;
Press either DC+ or DC- until you can see the polar telescope from the front opening of the
polar axis;
Focus the polar telescope eyepiece so you can see the markings inside;
Adjust the field illumination with the STAR BOOK so the markings can barely be seen;
Turn the Time Graduation Circle(the circle marked 0 through 23)to centre the bubble in the
water level;
Turn the Time Meridian Indicator to adjust the difference between the standard time meridian of
your region and your observing site. Example: The longitude of HKNEAC is 114.1ºE, it is 5.9º
west of the standard time meridian (120ºE). Turn the Time Meridian Indicator so that the
marking points at the 5.9ºW position on the Meridian Offset Scale;
Match the Date Graduation Circle with the current time by turning the eyepiece of the polar
telescope;
Look through the polar telescope and by using the Altitude Adjustment Knob and the Azimuth
Adjustment Knob, place the pole star somewhere along the 2005-2025 graduations. The exact
position depends the year of your observation.
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B
Initializing the Star Book
1
Make sure the mount is in the power off position ○ ;
Connect the mount to the power source;
2
Connect the Star Book to the mount. If it is a Star Book-S, make sure it is loaded with batteries;
3
Switch on the mount first I , then the Star Book-S . Wait for the Initial setting screen;
4
Press A/B(see picture below)then select 言語/Language from the menu and press E to
5
confirm;
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10
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Press A/B to select English,then E to confirm. This will bring you to the English root menu;
Now the bottom of the screen outlines the functions of the buttons;
Press A/B to select Local Time Setting, then E to confirm;
Press A/B to select an entry box. Press A/B to input the data;
Press A/B to select OK and E to confirm;
Do similarly to input your site;
After finishing the above steps, choose Save Setting to save your configuration into Star Book's
memory. Star Book will return to the Initial setting screen. Press OK and select Confirm after
reading the Warning;
In the home position screen select OK and enter the Scope Mode as suggested;
Press A、B、C、D to make sure the telescope can be slewed in all directions. Then slew it to the
Home position as in the picture below.
Two-star alignment
1
To make sure the telescope will correctly locate any object in the sky, it is important to align it
after setup;
2
After finishing Step 14 in the previous section select Yes to enter the Scope Mode;
3
There are two working modes built into the SXD mount, i.e. the Scope Mode and the Chart
4
Mode;
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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Under Scope Mode the mount will react instantly to the commands you input;
Under Chart Mode the mount will not react to your command unless the GOTO button is
selected;
To align your telescope, you must enter the Chart Mode , locate a bright star in the chart and
move it to the centre of the cross hair. The star should be well above the horizon and not
obstructed by anything;
Now press Zoom+ until you can see two circles centred on the cross hair. Keep the star within the
inner circle;
8
Keep pressing Zoom+ until the inner circle is at its biggest. Align the star with the centre of the
cross hair and then press GOTO and select confirm when asked;
9
10
The telescope will start slewing. Wait until a 'Beep' is heard;
Look through the finder scope (it should have been align with the main telescope before hand)
and centre the star by slewing with the control panel;
Look through a low to medium power eyepiece and bring the star to the centre of the field just as
you did in Step 10. You can refine the alignment using a high power eyepiece;
You will notice that the star in the star chart had drifted off the centre;
Press Align and confirm your choice;
11
12
13
You have just finished aligning one star. Now choose a second star (it should not be too close to
the first) and repeat Steps 6 through 13. After that your scope is properly aligned and ready for the
evening's events.
D
Hands-on
In Chart Mode select Object and choose from a list of recommendation to observe.
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Meade telescopes with Autostar
A Polar alignment
1 Setup your telescope on a level ground in an open space where you can easily find Polaris;
2 Remove the front and back covers of the polar telescope if there is any. Turn the Dec. Axis so the
telescope is not blocked;
3 Adjust the telescope to centre Polaris in the polar telescope.
B
Initialize the Autostar
1
The AUTOSTAR must be initialized when used for the first time or after a reset;
2
Make sure the mount is powered off. Then plug the control panel cable to the HBX socket in the
mount;
3
4
5
Connect the mount to a power source;
Switch on the power and AUTOSTAR will display a warning. Confirm to go on;
The menu will display two choices. Press ENTER to go to the next screen;
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AUTOSTAR will ask you to input the date. Use number keys and direction keys to do the input;
Use direction keys to advance to 'Month' and scroll to the desired month;
Use the direction keys to advance to 'Year' and use number keys to input the year;
Press ENTER to confirm;
Use number keys and direction keys to input the time and scroll to choose AM or PM;
Press ENTER to confirm;
When asked to use summer time, scroll to choose NO ;
Scroll to choose your city and press ENTER ;
Scroll to choose your telescope mount and press ENTER ;
Keep pressing MODE until Select Item: Object appears;
Scroll to select Select Item: Setup. Press ENTER to confirm;
Scroll to Setup: Telescope then to Telescope: Train Drive, press ENTER ;
Select Train Drive: Az/RA Train and press ENTER to confirm. This will train the RA axis motor
to work properly;
Release the axis lock levers and point the telescope to a far away object and centre it. Fasten the
levers again. Press ENTER ;
Your telescope will move off your target and the screen says: Press>until it is centered;
Press  until your target is centred again. Note: You MUST not use other keys. If you slew
pass your target you will have to start all over again from step 15;
After your target is centred, press ENTER to confirm;
Your telescope will move off your target again and the screen says: Press<until it is centered;
Press  until your target is centred again;
Now scroll to Train Drive: Alt/Dec Train and press ENTER;
Press ENTER again;
Now the telescope to ready to train the declination motor. The process is similar to the former
training. Finish the process as told.
Fine-tuning
1
Keep pressing MODE until Select Item: Setup appears. Then press ENTER;
2
Select Setup: Align and press ENTER. Then select Align: Easy and press ENTER;
The following example is for the more complicated German equatorial mount only. The screen
3
reads German North. Put the telescope in its 'Polar Home Position' and press ENTER;
'Polar Home Position' setup for equatorial mount is shown in the picture below;
4
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AUTOSTAR will drive the telescope to point at a bright star in the sky. If you are not sure or the
star is being obstructed, press  to let AUTOSTAR select another star;
If the selected star is spotted within the finder scope field use the direction keys to centre the star
(You should have aligned your finder scope beforehand);
Look through the telescope eyepiece and use the direction keys to centre the star. To further fine
tune the pointing accuracy, change to a high power eyepiece to finish the job;
After the star is centred, press ENTER. The telescope will move on to a second star. Do the same
as before;
Press ENTER to complete the process.
D
Simple operation
1
AUTOSTAR comes with a Guided Tour. It is extremely useful for fresh starters. It will
recommend to the user a list of objects available for the specific observation session;
2
Just keep pressing MODE until Select Item: Object appears;
3
Scroll to Select Item: Tonight’s Best(other choices are also available). Press ENTER;
The screen will recommend the first object. Press ENTER and the screen to outline information
4
of the selected object. Press GOTO to start the automatic slewing. Wait until a 'beep' is heard and
you are ready to observe;
5
Press MODE to choose another object;
6
To exit Guided Tour press MODE for 2 seconds.
E
The Autostar menu
1 You can use the scroll keys ( 
 ) to navigate among the menu items;
2 You can use the ENTER key to confirm your choice;
3 You can use the MODE key to return to the previous menu level;
4 The following picture summarizes the functions of the Autostar control unit.
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The Celestron GT mount
A Polar alignment
1 Setup your telescope on a level ground in an open space where you can see Polaris;
2 Centre Polaris in your polar finder.
B
Initialization
1 Connect the control panel to the telescope mount and switch on the power;
2 Align the index marks found on both axes of your mount. Then press ENTER;
3 The screen will display the basic information entered in the last session. Scroll to run through it.
If the information is still applicable, press ENTER. If not, press UNDO and input as directed;
4 To correct a wrong input just press UNDO and retype. When everything is OK press ENTER.
C
Fine tuning
1 Having finished the above steps the Alignment menu will appear. Use the UP or DOWN keys
to select Two Star Align and press ENTER;
2 The scope will slew to the first alignment star. If the star is obstructed press UNDO to select
another. Then press ENTER to confirm your selection;
3 The scope will then slew to the selected star. Use the direction keys to centre the star in the finder
scope. Then press ENTER;
4 Note: You can change the slew rate when using the direction keys. Press RATE and then choose
from keys 1 through 9 . 1 is slowest and 9 fastest. You should use a slower slew rate
when looking through an eyepiece;
5 Now look through a low power eyepiece and centre the star in the field. You can fine tune the
accuracy by using a medium to high power eyepiece next. After that press ALIGN;
6 The scope will now slew to the second alignment star. Repeat the centring process;
7 After that the system will ask if you wish to select a third alignment star. Press UNDO to leave.
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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Simple operation
1 Nexstar comes with a tour guide which is very helpful for beginners. Just press TOUR and the
telescope will act as your guide to tour round the night sky;
2 You can also choose other objects of interest. Just press the appropriate key to select from the
menu;
3 You can press INFO to view information of a selected object. Then press ENTER to start the
GoTo;
4 You can also press PLANET to see which planets are above the horizon for observation and select
accordingly.
Non-GoTo telescopes
1 A telescope that has no goto function cannot be used as an SGT. However, as long as it is
equipped with tracking motors and properly polar aligned, it can still be used for observation and
astrophotography. Teachers are reminded to avoid using this kind of telescopes when they have to
handle a large class of students;
2 A non-goto telescope should always be accompanied by a very detail map, one with stars up to
the 9th magnitude or fainter. The map can serve as deep-sky object finder charts. A good
planetarium software with a suitable star data base is a good choice;
3 A good quality polarscope and finderscope are a must. You should always make sure the
finderscope is carefully aligned with the main telescope too;
4 The following 'star hop' process illustrates how to look up an object manually. As an example, we
are to find the minor planet Ceres on 7th of May, 2009. First locate Ceres in a finder chart. Look
for some nearest bright stars;
5 Locate one of these stars in the finder scope and make it as the starting point of your star hop;
6
Centre the 1st star in the finder so that it is also visible within a low power eyepiece in the main
scope. Remember you have an inverted field in an astronomical telescope. If you are using a
Newtonian or observing with a diagonal, then either the left and right or the up and down of the
field will be inverted. If you are using a software star chart you may invert and rotate to chart to
fit your observation;
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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7
Plan your star hop route to Ceres;
8
Use a medium rate and slew the telescope from one star to the next while looking through a low
power / wide field eyepiece. Pause to consult the finder chart to make sure you don't stray off
target;
After you have pinpointed Ceres you can choose a more suitable power for observation or set up
your photography equipment.
9
Suggested learning activities
Controlling a telescope is a basic skill for astronomical research. Teachers are recommended to give their
students some basic training.
1 Teach your students how to find Polaris (this is very basic skill);
2 Teach your students about the constellations and bright stars. They should master this skill for two-star
alignment;
3 Divide the students into small groups and give them the responsibility of setting up a telescope. It is
also important to let them have hands-on experience on different types of telescope if possible;
4 Let the students master the skill of polar alignment;
5 Let the students master the skill of two star alignment;
6 Prepare a list of objects to be observed during an observing session. The list may include objects not
yet risen above the eastern horizon and some that are low in the west. Students should make a plan to
observe as many objects as possible from the list;
7 Students should be able to drive their telescope to objects as they have planned. They should observe
and give simple description of these objects;
8 Teachers have to evaluate the abilities of the students as well as their observations;
9 Try to make an observing session as lively and interesting as possible.
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
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Buying the first telescope
Ask yourself 5 questions before you make a buying decision:
1
2
3
4
5
Why buy a telescope?
Reasons:
The school is introducing astronomy into their curriculum.
The school will start an astronomy club.
What is the budget?
The price of an astronomical telescope ranges from a few thousand dollars up.
The price is also reflected in the quality and features.
You have to know how much the school is willing to spend.
How will the telescope be used?
Decide how the telescope will be used so you don't waste spending on features you won't be using.
A telescope for observing the planets is different from one used for observing deep-sky objects.
A planetary telescope should have long focal length (f/15~f/20) to achieve high magnifications.
A deep-sky telescope should have short focal length (f/5~f/8) to achieve a wide observable field.
In any case the larger the diameter of the lens / mirror the better.
Does the school intend to build a permanent observatory?
Air and light pollution is extremely heavy in HK. Unless you have a permanent observatory in the
country, a big and heavy telescope will become a burden when arranging activities. It is wise to start
with a lightweight telescope.
How is the observing condition of your school?
Is the school situated in a heavily polluted location?
Is your school surrounded by tall buildings?
Is it possible for your students to stay overnight?
After you have decided....
1
2
3
Never buy a telescope from a camera shop in HK.
Make sure the telescope you choose has all the features you need. It doesn't have to be your dream
telescope.
Search and investigate before you buy. Look up test reports. Ask for advice from other users.
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Local telescope and accessaries suppliers
Note: Always check the suppliers' web sites before ordering.
Grandeye Scientific Company 巨眼天文儀器社
Tel: (852) 9638 3899
http://www.grandeye.com.hk/
Sun Sing Scientific Company 日 昇 儀 器
Tel: (852) 9361 3351, (852)2320 9770
http://www.scopehouse.com/Home.htm
Galaxy Scientific Group 星河科研社
Tel: (852) 81060660
http://www.astro.org.hk/services.html
Tat's Telescope 達氏望遠鏡
Tel: (852)9218 2440
傳真: (852)2475 6780
http://www.william-lt-ng.com/Vixen/Photo_accessory.htm
Hong Kong Astro Equipment 香港天文儀器
電 話 : (852) 9355 5397
http://www.hkastroequipment.com/
Achievers Track 卓越策劃
Tel: (852) 2714 9284
傳真: (852) 8343 2812
http://www.a-track.net/
Tan14
Email: peter@tan14.com
http://www.tan14.com/gears.htm
Stargazer Telescope and Accessory Company 觀星者天文儀器社
Tel: (852)92737658
http://www.stargazer.hk/
Many foreign astronomical equipment companies have their own web sites. They provide
detailed information on telescopes they supply. Some even let you compare features of telescopes
from different manufactures side by side.
Oceanside Photo & Telescope
http://www.optcorp.com/
Adirondack Video Astronomy
http://www.astrovid.com/
Cloudy Nights Telescope Review
http://www.cloudynights.com/
Scope City, Inc
http://www.scopecity.com/
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Telescope terminology
You might often come across some astronomy terms when choosing your first telescope or while reading
the instruction manual of your new telescope. You may find the following glossary helpful.
Glossary
Note
Optical design 光學設計
Achromatic Refractor 消色差折射鏡
Newtonian 牛頓式反射鏡
Schmidt-Newtonian 史密特-牛頓式反射鏡
Maksutov-Cassegrain 馬蘇托夫-卡塞格林式
A catadioptric telescope design.
Schmidt- Cassegrain 史密特-卡塞格林式
A catadioptric telescope design.
Dobsonian 杜蘇式
A simple alt-azimuth mounted newtonian
telescope.
Lens / Mirror specification 主鏡規格
Aperture 口徑
The size of the main optical lens or mirror.
Bigger is better.
Focal Length 焦距
The distance from the lens to the focus.
Focal Ratio 焦比
F number of a lens. Calculated as f.l. / lens
dia.
Resolving power 分解力
A measurement of the ability to form a sharp
image. Unit of measurement is arc second.
Larger aperture has higher resolving power.
Secondary mirror 副鏡
A small mirror in a reflective system to direct
the light path to a desired position.
Telescope mounting 望遠鏡基座
Fork type 叉式
An Alt-Azm mount design.
Equatorial Mount 赤道儀
A telescope mount designed to counteract the
effect caused by earth's rotation.
Accessaries 配件
Diagonal 天頂菱鏡
Polarscope 極軸鏡
Eyepiece Focal Length 目鏡焦距
The focal length of an eyepiece. It can be used
to calculate the magnification of the resulting
image. M=f.l.lens / f.l.eyrpiece
Apparent field-of-view(FOV) 觀測視場
A measurement of the actual diameter (°) of
the observable field through an eyepiece.
Barrel diameter 目鏡筒徑
The size of an eyepiece barrel. Usually comes
in 1.25- or 2-inch sizes.
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Deep-sky objects
This list of deep-sky objects serves as a guide to beginners.
Con
Andromeda
Object
Type
M31, M32,
M110
Galaxy
NGC 7662
Planetary nebula
Almach, And γ
R. A.
h
Orange-Green Double
Dec.
m
00 42 44
23h 25m 54s
h
m
+41°16′ 9″
Andromeda galaxy
+42° 32′ 6″
Blue snowball nebula
s
+42° 19′ 47″
00h 48m 26s
+85° 15′ 18″
02 03 54
Nickname
star
Cepheus
NGC 188
Cep μ
Open cluster
Red star
h
m
s
h
m
s
+58° 17′ 12″
h
m
s
+61° 12′ 06″
h
m
s
+51° 34′
h
m
s
+57° 08′
Double cluster
+24° 7′
Pleiades
21 43 30
+58° 46' 48"
Herschel's Garnet
Star
Cassiopeia
NGC 457
NGC 7635
Perseus
Taurus
M76
M45
Open cluster
M1
M36
M37
M38
Monoceros
M42, M43
Gemini
Open cluster
Red star
SNR
Open cluster
Open cluster
Open cluster
Diffuse nebual
M78,
NGC 2071
Reflection nebual
NGC 2244
Open cluster
NGC 2237
Canis Major
Planetary nebula
Open cluster
Tau 119
Orion
Diffuse nebual
NGC 869,
NGC 884
Hyades
Auriga
Open cluster
M41
NGC 2392
Diffuse nebual
Open cluster
Planetary nebula
01 19 35
23 20 48
01 42 24
02 22 18
03h 47m 24s
Bubble nebula
h
m
h
m
s
+18°35′ 40″
Garnet star
h
m
s
+22° 00′ 52″
Crab nebula
h
m
s
+34° 08′ 4″
h
m
s
+32° 33′ 2″
h
m
s
+35° 51′ 18″
h
m
s
-05° 23′ 28″
h
m
s
+00° 04′ 48″
04 27
05 32 13
+15° 52′
05 34 32
05 36 12
05 52 19
05 28 42
05 35 17
05 46 45
06h 31m 54s
+4° 56′ 35″
h
m
h
06 46
m
h
m
s
h
m
s
+65° 36′ 09″
h
m
s
19° 41′
h
m
s
+69° 3′ 55″
h
m
s
+69° 40′ 47″
Cigar galaxy
h
m
s
+55° 01′
Owl nebula
h
m
s
-11° 37′ 23″
Sombrero galaxy
h
m
s
+47° 11′ 43″
Whirlpool galaxy
h
m
s
+36° 27′ 37″
h
m
s
-24° 23′ 12″
06 33 45
s
Orion nebula
-04° 59′ 54″
Rosette nebula
-20° 46′
07 29 11
+20° 54′ 43″
Eskimo / Clownface
nebula
Chamaeleon
Cancer
Ursa Major
NGC 2403
M44
M81
M82
M97
Virgo
Canis Venatici
Hercules
Sagittarius
M104
M51
M13
M8
Galaxy
Open cluster
Galaxy
Galaxy
Planetary nebula
Galaxy
Galaxy
Globular cluster
Diffuse nebual
07 36 51
08 40 24
09 55 33
09 55 52
11 14 48
12 39 59
13 29 53
16 41 41
18 03 37
Beehive
Lagoon nebula
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Using Computerized Telescope to Facilitate learning and teaching of “Astronomy And Space Science" in the New Senior Secondary Physics Curriculum
M20
Diffuse-reflection
18h 02m 23s
-23° 01′ 48″
Trifid nebula
18h 20m 26s
-16° 10′ 36″
Omega nebula
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nebual
M17
M22
Lyra
Lyr ε
M57
Cygus
Delphinus
Aquarius
Albireo, Cyg β
NGC 6905
NGC 7293
Diffuse nebual
Globular cluster
Double star
Planetary nebula
Double star
Planetary nebula
Planetary nebula
h
m
s
-23° 54′ 12″
h
m
s
+39° 40′ 12
Double double
h
m
s
+33° 01′ 45″
Ring nebula
h
m
s
+27° 57′ 35″
h
m
s
+20° 07′
h
m
s
-20° 50′ 14″
18 36 24
18 44 20
18 53 35
19 30 43
20 22 24
22 29 39
Helix nebula
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A whole-sky star map
Use this star map to learn the IAU constellations.
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© SFA Observatory
33
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