Celestron 91518 User manual

A
A
Ad dv va an nc ce ed d S Se er ri ie es s C CG G- -5 5 & & C CG G- -5 5 G G
GT
T
T
I
IN NS ST TR RU UC CT TI IO ON N M MA AN NU UA AL L
9
91 15 51 17 7 ● ● 9 91 15 51 18 8

1 Optical Tube 7 Tripod
2 Finderscope 8 Counterweight(s)
3 Finderscope Bracket 9 Counterweight Bar
4 Equatorial Mount 10 Declination Setting Circle
5 Latitude Adjustment Scale 11 Dovetail Mounting Bar
6 Tripod Center Leg Brace/Accessory Tray 12 Schmidt Corrector Lens
Figure 2.1 – Advanced Series
(Advanced C8-S Shown)
12
1
2
3
4
5
6
7
8
9
11
10

5
1 Optical Tube 9 Counterweight Bar
2 Finderscope 10 Declination Setting Circle
3 Finderscope Bracket 11 Dovetail Mounting Bar
4 Equatorial Mount 12 Schmidt Corrector Lens
5 Latitude Adjustment Scale 13 Hand Control
6 Tripod Center Leg Brace/Accessory Tray 14 R.A. Motor Drive / Control Panel
7 Tripod 15 Declination Motor Drive
8 Counterweight(s)
CONTROL PANEL C Autoguider Port
A Hand Control Port D 12v Output Jack
B DEC Motor Port E On/Off Switch
Figure 2.2 – Advanced Series GT
(Advanced C8-SGT Shown)
12
1
2
3
4
5
6
7
11
10
14
15
13
9
8
A
B
E
C
D

6
This section covers the assembly instructions for your Celestron Advanced Series CG-5 mount. Your mount
should come with all of the following:
CG-5 Mount CG-5 GT Mount,
Computerized
91517 91518
EQ Mount Head EQ Mount Head
2" steel tripod 2" steel tripod
Counterweight Bar Counterweight Bar
Counterweight Bar Coupling
Screw
Counterweight Bar Coupling
Screw
One- 11# Counterweight One- 11# Counterweight
Accessory Tray/Leg Brace Accessory Tray/Leg Brace
Central Rod with locking
knob (attached to tripod) Central Rod with locking knob (attached to tripod)
2- slow motion knobs
(attached) 2- slow motion knobs (attached)
RA housing cover RA housing cover
Mounting Adapter bar Mounting Adapter bar
Instruction Manual Instruction Manual
Hand control
Plastic hand control holder
(2 pieces)
Declination cable
Car battery adapter
The Celestron Advanced Series telescopes are shipped in two boxes (three boxes for GT models). In separate
boxes are the following:
•Optical Tube Assembly and Standard Accessories
•Equatorial Mount, Tripod, Hand Control, Counterweight(s) and Counterweight Bar (equatorial mount
with motors comes in separate box for GT models)
Remove all the pieces from their respective boxes and place on a flat, clear work area. A large floor space is
ideal. When setting up your Celestron telescope you must start with the tripod and work up from there. These
instructions are laid out in the order each task must be performed.
S
Se et tt ti in ng g u up p t th he e T Tr ri ip po od d
The CG-5 tripod comes with an all metal center leg brace / accessory tray to give rock solid support to the
mount.

7
The tripod comes fully assembled with a metal plate, called the tripod head, that holds the legs together at the
top. In addition, there is a central rod that extends down from the tripod head that attaches the equatorial mount
to the tripod. To set up the tripod:
1. Stand the tripod upright and pull the tripod legs apart until each leg is fully extended. The tripod will now stand
by itself. Once the tripod is set up, you can adjust the height at which it stands.
2. Loosen the lever on the leg clamp so that the tripod leg can be adjusted.
3. Slide the center portion of the tripod leg away from the tripod head until it is at the desired height.
4. Tighten the levers on each leg clamp to hold the legs in place.
A
At tt ta ac ch hi in ng g t th he e E Eq qu ua at to or ri ia al l M Mo ou un nt t
The equatorial mount allows you to tilt the telescope’s axis of
rotation so that you can track the stars as they move across the
sky. The CG-5 mount is a German equatorial mount that
attaches to the tripod head. On one side of the tripod head there
is a metal alignment peg for aligning the mount. This side of
the tripod will face north when setting up for an astronomical
observing session. To attach the equatorial head:
1. Locate the azimuth adjustment screws on the equatorial mount.
2. Retract the screws so they no longer extend into the azimuth
housing on the mount. Do NOT remove the screws since
they are needed later for polar alignment.
3. Hold the equatorial mount over the tripod head so that the
azimuth housing is above the metal peg.
4. Place the equatorial mount on the tripod head so that the two are flush.
5. Tighten the knob (attached to the central rod) on the underside of the tripod
head to hold the equatorial mount firmly in place.
A
At tt ta ac ch hi in ng g t th he e C Ce en nt te er r L Le eg g B Br ra ac ce e
1. Slide the accessory tray over the central rod so that each
arm of the tray is pushing against the inside of the tripod
legs.
2. Thread the accessory tray knob on to the central rod and
tighten.
Figure 2-4
Equatorial
Mount
Tripod
Head Alignment
Peg
Azimuth
Alignment Screws
Mounting
Knob
Mounting Knob
Central Rod
Accessory Tray
Accessory
Tray Knob
Figure 2-3
CG-5 Computerized Shown

8
I
In ns st ta al ll li in ng g t th he e C Co ou un nt te er rw we ei ig gh ht t B Ba ar r
To properly balance the telescope, the mount comes with a counterweight bar and one counterweight To install
the counterweight bar:
1. Thread the counterweight bar lock nut onto the threaded end of the
counterweight bar.
2. Locate the opening in the equatorial mount on the DEC axis
3. Thread the counterweight bar into the opening until tight.
4. Tighten the counterweight bar lock nut fully for added support.
Once the bar is securely in place you are ready to attach the
counterweight.
Since the fully assembled telescope can be quite heavy, position
the mount so that the polar axis is pointing towards north
before the tube assembly and counterweights are attached.
This will make the polar alignment procedure much easier.
I
In ns st ta al ll li in ng g t th he e C Co ou un nt te er rw we ei ig gh ht t
Depending on which AST telescope you have, you will receive either one or two counterweights. To install the
counterweight(s):
1. Orient the mount so that the counterweight bar points toward the ground .
2. Remove the counterweight safety screw on the end of the counterweight bar (i.e., opposite the end that
attaches to the mount).
3. Loosen the locking screw on the side of the counterweight.
4. Slide the counterweight onto the shaft (see Figure 2-5) .
5. Tighten the locking screw on the side of the weight to hold the counterweight in place.
6. Replace the counterweight safety screw .
Figure 2-3
Counterweight
Safety Screw
Counterweight
Bar
Locking Screw
Lock Nut

9
A
At tt ta ac ch hi in ng g t th he e H Ha an nd d C Co on nt tr ro ol l H Ho ol ld de er r
(
(A Ad dv va an nc ce ed d G GT T M Mo od de el ls s O On nl ly y) )
The Advanced GT telescope models come with a hand control
holder to place the computerized hand control. The hand control
holder comes in two pieces: the leg clamp that snaps around the
tripod leg and the holder which attaches to the leg clamp. To
attach the hand control holder:
1. Place the leg clamp up against one of the tripod legs and
press firmly until the clamp wraps around the leg.
2. Slide the back of the hand control holder downward into
the channel on the front of the legs clamp (see Fig 2-
6 ) until it snaps into place.
A
At tt ta ac ch hi in ng g t th he e S Sl lo ow w M Mo ot ti io on n K Kn no ob bs s
(
(F Fo or r N No on n- -G GT T M Mo od de el ls s O On nl ly y) )
The Advanced Series (non-GT models) comes with two slow motion control knobs that allows you to make
fine pointing adjustments to the telescope in both
R.A. and Declination. To install the knobs:
1. Locate the hard plastic shell under the R.A. shafts.
2. Remove either of the two oval tabs by pulling
tightly.
3. Line up the flat area on the inner portion of the R.A.
slow motion knob with the flat area on the R.A.
shaft (see Fig 2-7).
4. Slide the R.A. slow motion knob onto the R.A.
shaft.
The knob is a tension fit, so sliding it on holds it in
place. As mentioned above, there are two R.A.
shafts, one on either side of the mount. It makes no difference which shaft
you use since both work the same. Use whichever one you find more
convenient. If, after a few observing sessions, you find the R.A. slow motion knob is more accessible from the
other side, pull firmly to remove the knob, then install it on the opposite side.
5. The DEC slow motion knob attaches in the same manner as the R.A. knob. The shaft that the DEC slow motion
knob fits over is toward the top of the mount, just below the telescope mounting platform. Once again, you
have two shafts to choose from. Use the shaft that is pointing toward the ground. This makes it easy to reach
while looking through the telescope, something which is quite important when you are observing.
Hand Control
Holder
Leg Clamp
Figure 2-6
Figure 2-7
Figure 2-5

10
A
At tt ta ac ch hi in ng g a an n O Op pt ti ic ca al l T Tu ub be e t to o t th he e M Mo ou un nt t
An optical tube attaches to the mount via a dovetail bar which mounts along the
bottom of a telescope tube. The CG-5 mount comes with a mounting bar that
mates to the mounting head of the mount. The mounting bar can be used to
attached a desired telescope to the CG-5 mount. Before you attach an optical
tube, make sure that the declination and right ascension clutch knobs are
tight. This will ensure that the mount does not move suddenly while attaching the
telescope. To mount the telescope tube:
In order for the GT computerized mount to function properly, before installing
an optical tube, the mounting platform must be positioned so that the
Declination Index Marks are aligned (see Fig 2-8).
1. Loosen the mounting screw on the side of the telescope mounting platform. This allows you to slide the
dovetail bar onto the mount.
2 Slide the dovetail bar on the telescope tube into the mounting platform of the mount.
3 Tighten the mounting screw on the side of the mounting platform to hold the telescope in place.
M
Mo ov vi in ng g t th he e T Te el le es sc co op pe e M Ma an nu ua al ll ly y
In order to properly balance your telescope, you will need to move your
telescope manually at various portions of the sky to observe different
objects. To make rough adjustments, loosen the R.A. and DEC clutch
knobs slightly and move the telescope in the desired direction.
Both the R.A. and DEC axis have lock levers to clutch down each axis
of the telescope. To loosen the clutches on the telescope, rotate the lock
levers counterclockwise.
B
Ba al la an nc ci in ng g T Th he e M Mo ou un nt t i in n R R. .A A. .
To eliminate undue stress on the mount, the telescope should be
properly balanced around the polar axis. Proper balancing is crucial for
Advanced
GT Users!
Dovetail Bar
Telescope
Mounting Screw
Declination
Lock Lever
R.A. Lock Lever
Declination
Index Marks
Figure 2-8
Figure 2-9

11
accurate tracking. To balance the mount:
1. Verify that the telescope is securely attached to the telescope mounting platform.
2. Loosen the R.A. lock lever and position the telescope off to one side of the mount. The
counterweight bar will extend horizontally on the opposite side of the mount.
3. Release the telescope — GRADUALLY — to see which way the telescope “rolls.”
4. Loosen the set screws on the side of the counterweight so it can be moved the length of the
counterweight bar.
5. Move the counterweight to a point where it balances the telescope (i.e., the telescope remains
stationary when the R.A. clutch knobs are loose).
6. Tighten the screw on the counterweight to hold it in place.
While the above instructions describe a perfect balance arrangement, there should be a SLIGHT imbalance to
ensure the best possible tracking. When the scope is on the west side of the mount the counterweight should be
slightly imbalanced to the counterweight bar side. And when the tube is on the east side of the mount there
should be a slight imbalance toward the telescope side. This is done so that the worm gear is pushing against a
slight load. The amount of the imbalance is very slight. When taking astrophotographs, this balance process
can be done for the specific area at which the telescope is pointing to further optimize tracking accuracy.
B
Ba al la an nc ci in ng g T Th he e M Mo ou un nt t i in n D DE EC C
Although the telescope does not track in declination, the telescope should also be balanced in this axis to
prevent any sudden motions when the DEC lock lever is loose. To balance the telescope in DEC:
1. Loosen the R.A. clutch lock lever and rotate the telescope so that it is on one side of the mount
(i.e., as described in the previous section on “Balancing the Mount in R.A.”).
2. Tighten the R.A. lock lever to hold the telescope in place.
3. Loosen the DEC clutch lock lever and rotate the telescope until the tube is parallel to the ground.
4. Release the tube — GRADUALLY — to see which way it rotates around the declination axis.
DO NOT LET GO OF THE TELESCOPE TUBE COMPLETELY!
5. Slightly loosen the knobs that holds the telescope to the mounting platform and slide the telescope
either forward or backward until it remains stationary when the DEC clutch is loose. Do NOT let
go of the telescope tube while the knob on the mounting platform is loose. It may be necessary to
Figure 2-13
Figure 2-12

12
rotate the telescope so that the counterweight bar is pointing down before loosening the mounting
platform screw.
6. Tighten the knobs on the telescope mounting platform to hold the telescope in place.
Like R.A. balance, these are general balance instructions and will reduce undue stress on the mount. When
taking astrophotographs, this balance process should be done for the specific area at which the telescope is
pointing.
A
Ad dj ju us st ti in ng g t th he e M Mo ou un nt t
In order for a motor drive to track accurately, the telescope’s axis of rotation must be parallel to the Earth’s
axis of rotation, a process known as polar alignment. Polar alignment is achieved NOT by moving the telescope
in R.A. or DEC, but by adjusting the mount vertically, which is called altitude, and horizontally, which is called
azimuth. This section simply covers the correct movement of the telescope during the polar alignment process.
The actual process of polar alignment, that is making the telescope’s axis of rotation parallel to the Earth’s, is
described later in this manual in the section on “Polar Alignment.”
Adjusting the Mount in Altitude
• To increase the latitude of the polar axis, tighten the rear latitude adjustment screw and loosen the front screw
(if necessary).
• To decrease the latitude of the polar axis, tighten the front (under the counterweight bar) latitude
adjustment screw and loosen the rear screw (if necessary).
The latitude adjustment on the CG-5 mount has a range from approximately 30° going up to 60°.
It is best to always make final adjustments in altitude by moving the mount against gravity (i.e. using the rear
latitude adjustment screw to raise the mount). To do this you should loosen both latitude adjustment screws and
manually push the front of the mount down as far as it will go. Then tighten the rear adjustment screw to raise
the mount to the desired latitude.
For Advanced GT users, it may be helpful to remove the front latitude adjustment screw completely. This will
allow the mount to reach lower latitudes without the screw coming into contact with R.A. motor assembly. To
remove the latitude screw, first use the rear screw to raise the mount head all the way up. Then remove the
front latitude screw completely. Now you should be able to
manually move the mount head all the way to it lowest latitude.
Now, using only the rear screw, raise the mount to your desired
latitude.
Adjusting the Mount in Azimuth
For rough adjustments in azimuth, simply pick up the telescope and
tripod and move it. For fine adjustments in azimuth:
1. Turn the azimuth adjustment knobs located on either side of the
azimuth housing. While standing behind the telescope, the knobs
are on the front of the mount.
• Turning the right adjustment knob clockwise moves the mount toward the right.
• Turning the left adjustment knob clockwise moves the mount to the left.
Figure 2-14
Azimuth
Adjustment
Knobs
Rear Latitude
Adjustment
Screws
Front Latitude
Adjustment Screw

13
Both screws push off of the peg on the tripod head, which means you may have to loosen one screw while
tightening the other. The screw that holds the equatorial mount to the tripod may have to be loosened slightly.
Keep in mind that adjusting the mount is done during the polar alignment process only. Once polar aligned, the
mount must NOT be moved. Pointing the telescope is done by moving the mount in right ascension and
declination, as described earlier in this manual.
A
At tt ta ac ch hi in ng g t th he e D De ec cl li in na at ti io on n C Ca ab bl le es s ( (F Fo or r G GT T M Mo od de el ls s O On nl ly y) )
The Advanced Series mount comes with a declination cable that connect s from the R.A. motor drive electronic
panel to the Dec motor drive. To attach the motor
cables:
•Locate the Declination cable and
plug one end of the cable into the
port on the electronics panel labeled
DEC Port and plug the other end of
the cable into the port located on the
declina tion motor drive (see
Fig 2-15 ).
P
Po ow we er ri in ng g t th he e T Te el le es sc co op pe e
The Advanced GT can be powered by the
supplied car battery adapter or optional 12v AC
adapter. Use only adapter s supplied by
Celestron. Using any other adapter may damage
the electronics and will void your manufacturer's
warranty.
1. To power the telescope with the car battery adapter (or 12v AC adapter), simply plug the round post
into the 12v outlet on the electronic panel and plug the other end into your cars cigarette lighter outlet
or portable power supply (see Optional Accessories). Note: to prevent the power cord from being
accidentally pulled out, wrap the power cord around the strain relief located below the power switch.
2. Turn on the power to the telescope by flipping the switch, located on the electronics panel, to the "On"
position.
Declination Cable
Output Port
Declination Cable
Input Port
12v Power Input
On/Off Switch
Figure 2-15

14
The following is a supplemental addendum to the included instruction manual that
explains the new features of Celestron's Advanced Series Telescopes. Please refer to this
addendum for information concerning the new hand control features included with
your telescope. Refer to the owner's manual for step-by-step instruction on assembling
and using your telescope.
The Advanced Series GT, computerized version of each telescope has a hand controller
designed to give you instant access to all the functions that your telescope has to offer. With
automatic slewing to over 40,000 objects, and common sense menu descriptions, even a
beginner can master its variety of features in just a few observing sessions. Below is a brief
description of the individual components of the computerized hand controller:
1. Liquid Crystal Display (LCD) Window: Has a dual-line, 16 character display
screen that is backlit for comfortable viewing of telescope information and scrolling
text.
2. Align: Instructs the telescope to use a selected star or object as an alignment position.
3. Direction Keys: Allows
complete control of the
telescope in any
direction. Use the
direction keys to move
the telescope to
the initial alignment
stars or for centering
objects in the eyepiece.
1
2
3
7
8
9
10
4

15
4. Catalog Keys: The Advanced Series has keys on the hand control to allow direct
access to each of the catalogs in its database. The hand control contains the following
catalogs in its database:
Messier – Complete list of all Messier objects.
NGC – Complete list of all the deep-sky objects in the Revised New General
Catalog.
Caldwell – A combination of the best NGC and IC objects.
Planets - All 8 planets in our Solar System plus the Moon.
Stars – A compiled list of the brightest stars from the SAO catalog.
List – For quick access, all of the best and most popular objects in the Advanced
GT database have been broken down into lists based on their type and/or common
name:
Named Stars Common name listing of the brightest stars
in the sky.
Named Objects
Alphabetical listing of over 50 of the most
popular deep sky objects.
Double Stars Numeric-alphabetical listing of the most
visually stunning double, triple and
Figure 3
-
1
The Advanced GT Hand Control

16
quadruple stars in the sky.
Variable Stars Select list of the brightest variable stars
with the shortest period of changing
magnitude.
Asterisms A unique list of some of the most
recognizable star patterns in the sky.
CCD Objects A custom list of many interesting galaxy
pairs, trios and clusters that are well suited
for CCD imaging with the Advanced GT
telescope.
IC Objects A complete list of all the Index Catalog
deep-sky objects.
Abell Objects A custom list of the Abell Catalog deep-
sky galaxies.
Constellation A complete list of all 88 constellations.
5. Info:Displays coordinates and useful information about objects selected from the
Advanced GT database.
6. Tour: Activates the tour mode, which seeks out all the best objects for the current
date and time, and automatically slews the telescope to those objects.
7. Enter: Pressing Enter allows you to select any of the Advanced GT functions and
accept entered parameters.
8. Undo: 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. Menu: Displays the many setup and utilities functions such as tracking rates and user
defined objects and many others.
10. Scroll Keys: 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. Rate: Instantly changes the rate of speed of the motors when the direction buttons
are pressed.
12. RS-232 Jack: Allows you to interface with a computer and control the telescope
remotely.
Hand Control Operation
This section describes the basic hand control procedures needed to operate the Advanced GT
Series Telescopes. These procedures are grouped into three categories: Alignment, Setup
and Utilities. The alignment section deals with the initial telescope alignment as well as
finding objects in the sky; the setup section discusses changing parameters such as tracking
mode and tracking rate; finally, the last section reviews all of the utilities functions such as
calibrating your mount, polar alignment and backlash compensation.

17
A
Al li ig gn nm me en nt t P Pr ro oc ce ed du ur re es s
In order for the telescope to accurately point to objects in the sky, it must first be aligned
with known positions (stars) in the sky. With this information, the telescope can create a
model of the sky, which it uses to locate any object with known coordinates. There are many
ways to align your telescope with the sky depending on what information the user is able to
provide: Two Star Align uses the entered time/location information and allows the user to
select which two alignment stars the telescope will automatically slew to. One Star Align
uses the same time/location information but only uses one star for alignment. Solar System
Align will display a list of visible daytime objects (planets and the moon) available to align
the telescope. Quick-Align will ask you to input all the same information as you would for
the other Alignment procedures. However, instead of slewing to the alignment stars for
centering and alignment, the telescope bypasses this step and simply models the sky based on
the information given. Finally, Last Alignment restores your last saved star alignment and
switch position. Last Alignment also serves as a good safeguard in case the telescope should
lose power.
S
St ta ar rt tu up p P Pr ro oc ce ed du ur re e
Before any of the described alignments are performed, the telescope mount needs to be
positioned so that the index marks are aligned on both the right ascension and declination
axes (see Fig 2-8).
Once the index position has been set, the hand control will display the last entered date and
time information stored in the hand control. Once the telescope is powered on:
1. Press ENTER begin the alignment process.
2. The hand control will ask the user to set the mount to its index position. Move the
telescope mount, either manually or with the hand control, so that the index marked in
both R.A. and Dec are aligned (see Fig 2-8). Press Enter to continue.
3. The hand control will then display the last entered local time, date, time zone,
longitude and latitude.
•Use the Up/Down keys (10) to view the current parameters.
•Press ENTER to accept the current parameters.
•Press UNDO to enter current date and time information into the hand control.
The following information will be displayed:
Location - The hand control will display a list of cities to choose from. Choose the
city from the database that is closest to your current observing site. The city
you choose will be remembered in the hand controls memory so that it will be
automatically displayed the next time an alignment is done. Alternatively, if
you know the exact longitude and latitude of your observing site, it can be
entered directly into the hand control and remembered for future use as well.
To choose a location city:
 Use the Up and Down scroll keys to choose between City Database and Custom Site.
City Database will allow you to select the closest city to your observing site from a

18
list of either international or U.S. location. Custom Site allows you to enter the exact
longitude and latitude of your observing site. Select City Database and press ENTER.
 The hand control will allow you to choose from either U.S. or international locations.
For a listing of U.S. locations by state and then by city, press ENTER while United
United United
United
States
StatesStates
States is displayed. For international locations, use the Up or Down scroll key to
select International
InternationalInternational
International and press ENTER.
 Use the Up and Down Scroll buttons to choose your current state (or country if
International locations was selected) from the alphabetical listing and press ENTER.
 Use the Up and Down Scroll buttons to choose the closest city to your location from
the displayed list and press ENTER.
Time - Enter the current local time for your area. You can enter either the
local time (i.e. 08:00), or you can enter military time (i.e. 20:00 ).
• Select PM or AM. If military time was entered, the hand control will bypass
this step.
• Choose between Standard time or Daylight Savings time. Use the Up and
Down scroll buttons (10) to toggle between options.
• Select the time zone that you are observing from. Again, use the Up and
Down buttons (10) to scroll through the choices. Refer to Time Zone map in
Appendix for more information.
Date - Enter the month, day and year of your observing session.
4. Select one of the alignment methods as described below.
Note: If incorrect information is entered into the hand control, the UNDO button acts like a back space button
allowing the user to re-enter the correct data.
T
Tw wo o S St ta ar r A Al li ig gn n
Two-Star Align allows the user to select two stars on which to align the telescope. To align your telescope using
the Two-Star Align method:
1. Select Two-Star Align from the alignment choices given. Based on the date and time information
entered, the hand control will automatically select and display a bright star that is above the horizon.
•Press ENTER to select this star as your first alignment
star.
•If for some reason the chosen star is not visible
(perhaps behind a tree or building) press UNDO to
have the hand control automatically select the next
brightest star.
•Or you can use the Up/Down keys to browse the entire
Named Star list and select any one of over two hundred
alignment stars.
• The hand control will only display stars on
one side of the Meridian. To display
alignment stars on the opposite side of the
Mount Calibration
After a Two Star Alignment is
successfully completed, the hand
control will ask if you wish to add
calibration stars.
Adding calibration stars is necessary
to calculate and compensate for
"cone" error inherent in all German
equatorial mounts. Cone error is the
inaccuracy that results from the
optical tube not being exactly
perpendicular to the mount’s
declination axis. The telescope is
able to automatically determine the
cone error value by always using
calibration stars on the opposite
side of the Meridian from the
alignment stars. (see Figure 3-2)

19
Meridian, simply press the MENU button before selecting your first alignment
star. By default, Meridian filtering is enabled with the side of the Meridian that
has the largest number of stars above the horizon. Meridian filtering is indicated
in the upper right hand corner of the LCD display with an “E” (East) or “W”
(West). If nothing appears in the corner of the LCD, Meridian filtering is not
enabled.
2. Once the telescope is finished slewing to your first alignment star, the display will ask you to use the
arrow buttons to align the selected star with the cross hairs in the center of the finderscope. When
centered in the finder, press ENTER.
3. The display will then instruct you to center the star in
the field of view of the eyepiece. When the star is
centered, press ALIGN to accept this star as your first
alignment star.
4. After the first alignment star has been entered the hand
control will automatically select a second alignment
star and have you repeat this procedure for that star.
When the telescope has been aligned on both stars the
display will ask you if you wish to add any additional
calibration stars. Calibration stars are used to improve the
pointing accuracy of your telescope by compensating for
subtle optical-mechanical misalignments between the
telescope optics and the mount. Therefore it is usually a
good idea to add at least two additional calibration stasr to
improve the telescope’s all-sky pointing accuracy. If you
choose not to add any additional calibration stars you can
always add them later after a successful alignment has been
completed (see Improving Pointing Accuracy section
below).
5. Press ENTER to select a calibration star. Select a star the same way you did with the first two
alignments stars and press ENTER. You will notice that all the calibration stars displayed are located
on the opposite side of the side of the sky (Meridian) as the original alignment stars. This is essential
for an accurate calibration of the mount.
Finally you can choose to continue to add additional calibration stars or Press UNDO to complete the
alignment.
Tips for adding calibration stars:
•It is recommended that users add at least two calibration stars for optimal point accuracy.
•Calibration stars that are near the poles are intentionally filtered out because they can result in a
less accurate calibration.
•Although it is not be necessary to use calibration stars if the telescope mount has not been moved
since its original alignment/calibration, it may be necessary to add calibration stars if the optical
tube has been removed for any reason.
O
On ne e S St ta ar r A Al li ig gn n
Figure
3
-
2
The Meridian is an imaginary line in the sky
that starts at the North celestial pole and
ends at the South celestial pole and passes
through the zenith. If you are facing South,
the meridian starts from your Southern
horizon and passes directly overhead to the
North celestial pole.

20
One-Star Alignment works much the same way as Two-Star Align but uses only a single star
in the sky for alignment. This method of alignment is not as accurate as the two-star
alignment and is recommended only for telescopes that are permanently and accurately polar
aligned.
S
So ol la ar r S Sy ys st te em m A Al li ig gn n
Solar System Align is designed to provide excellent tracking and GoTo performance by
using solar system objects (Sun, Moon and planets) to 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 nighttime observing.
Never look directly at the sun with the naked eye or with a telescope (unless you have
the proper solar filter). Permanent and irreversible eye damage may result.
1. Select Solar System Align from the alignment options.
2. The SELECT OBJECT message will appear in the top row of the display. Use the Up and Down scroll keys (10) to
select the daytime object (planet, moon or sun) you wish to align. Press ENTER.
3. Use the direction arrow buttons to carefully center the object in the finderscope. Press ENTER when centered.
4. Then, center the object in the eyepiece and press ALIGN.
Once in position, the telescope will model the sky based on this information and display
Alignment Successful
Alignment SuccessfulAlignment Successful
Alignment Successful.
Tips for Using Solar System Align
•For safety purposes, the Sun will not be displayed in any of the hand control’s customer object lists unless it is
enabled from the Utilities Menu. To allow the Sun to be displayed on the hand control, do the following:
1. Press the UNDO button until the display reads “Advanced GT”
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.
•To improve the telescope pointing accuracy, you can add alignment stars as described in the Improving Pointing
Accuracy section below.
Q
Qu ui ic ck k- -A Al li ig gn n
Quick-Align uses all the date and time information entered at startup to align the telescope. However, instead of slewing to
the alignment stars for centering and alignment, the telescope bypasses this step and simply models the sky based on the
information given. This will allow you to roughly slew to the coordinates of bright objects like the moon and planets and
gives the telescope the information needed to track objects in any part of the sky (depending on accuracy of polar
alignment). Quick-Align is not meant to be used to accurately locate small or faint deep-sky objects or to track objects
accurately for photography.
To use Quick-Align, simply select Quick Align from the alignment options and press ENTER. The telescope will
automatically use the entered date/time parameters to align itself with the sky and display Alignment Successful.
NOTE: Once a Quick-Align has been done, you can add alignment and/or calibration stars to improve your telescopes
pointing accuracy. See the Pointing Accuracy section below for details.

21
L
La as st t A Al li ig gn nm me en nt t
The Last Alignment method will automatically recall the last stored index positions to
continue using the alignment that was saved when the telescope was last powered down.
This is a useful feature should your telescope accidentally lose power or be powered down.
NOTE: Just like with Quick-Align, you can use the Alignment Stars or Sync feature (see
below) to improve your telescopes pointing accuracy after using the Last Alignment method.
If the mount has not moved since the previous alignment then it is recommended to use Sync
to improve the pointing accuracy of your mount. However, if the mount has been moved
then changing alignment stars is the best way to re-align your mount.
To maintain a more accurate alignment over a series of observing sessions, use the Hibernate
feature described later in this chapter.
I
Im mp pr ro ov vi in ng g P Po oi in nt ti in ng g A Ac cc cu ur ra ac cy y
The Advanced Series telescopes have several options that allow you to improve the pointing accuracy of your
mount in a variety of ways.
Alignment Stars:
Alignment stars allows you to replace any of the original alignment stars with a new star or
celestial object. This can be useful if you have aligned your telescope using the Quick-Align
method. You can add alignment stars to align the telescope on actual objects in the sky.
This will improve the pointing accuracy of your telescope without having to re-enter addition
information.
To replace an existing alignment star with a new alignment star:
1. Select the desired star (or object) from the database and slew to it.
2. Once centered, press the UNDO button until you are at the main menu.
3. With Advanced GT displayed, press the ALIGN key on the hand control.
4. Use the Up/Down buttons and select the Alignment Stars option and press ENTER.
5. The display will then ask you which alignment star you want to replace. Use the UP
and Down scroll keys to select the alignment star to be replaced and press ENTER. It
is usually best to replace the star closest to the new object. This will space out your
alignment stars across the sky.
6. Align the star in the center of the finderscope and press ENTER.
7. Carefully center the object in the center of the eyepiece and press ALIGN
Calibration Stars:
Calibration stars are used to improve the pointing accuracy of your telescope’s mount by
compensating for misalignments between the telescope optics and the mount
To add calibration stars:

22
1. Select the desired star (or object) from the database and slew to it.
2. Once centered, press the UNDO button until you are at the main menu.
3. With Advanced GT displayed, press the ALIGN key on the hand control.
4. Use the Up/Down buttons and select the Calib Stars option and press ENTER.
5. Align the object in the center of the finderscope and press ENTER.
6. Carefully center the object in the center of the eyepiece and press ALIGN.
7. Use the Up/Down arrow keys to assign a number for the star and press ENTER.
To add additional calibration stars, repeat steps 1-6 again.
Tips for adding calibration stars:
•Make sure that the calibration stars that you choose are on the other side of the
meridian from the alignment stars that you used to align the telescope.
Sync:
The Sync feature can be used to improve pointing accuracy in a specific region of the sky.
Sync is a very useful feature especially when used in conjunction with the Constellation tour
and Identify feature in which you will be exploring smaller areas of the sky. To Sync on an
object:
1. Select the desired star (or object) from the database and slew to it.
2. Once centered, press the UNDO button until you are at the main menu.
3. With Advanced GT displayed, press the ALIGN key on the hand control.
4. Use the Up/Down buttons and select the Sync option and press ENTER.
5. Align the Sync object in the center of the finderscope and press ENTER.
6. Carefully center the object in the center of the eyepiece and press ALIGN.
Your telescope’s pointing accuracy will now be improved in that area of the sky.
NOTE: Sync can improve your telescope’s pointing accuracy over a wide area or over
smaller areas of the sky depending on the quality of the initial alignment, as well as where
the telescope was pointing when the Sync was done.
Undo Sync:
Since doing a Sync can affect your pointing accuracy in other parts of the sky, it may be
necessary to ‘Un-Sync” your telescope when exploring other parts of the sky. Doing an
Undo Sync will restore the pointing of your telescope to its original alignment. Additionally,
if you wish to add calibration stars or re-alignment stars you will be asked to do an Undo
Sync before you will be able to proceed
O
Ob bj je ec ct t C Ca at ta al lo og g
Selecting an Object