Celestron NexStar 90 MAK User manual

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IN NS ST TR RU UC CT TI IO ON N M MA AN NU UA AL L
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Ɣ N Ne ex xS St ta ar r 9 90 0 M MA AK K Ɣ Ɣ N Ne ex xS St ta ar r 1 12 27 7 M MA AK K
ENGLISH
CELESTRON®

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TA AB BL LE E O OF F C CO ON NT TE EN NT TS S
INTRODUCTION ............................................................................................................................................................ 4
Warning .......................................................................................................................................................................... 4
ASSEMBLY ...................................................................................................................................................................... 6
Assembling the NexStar ................................................................................................................................................. 6
Attaching the Hand Control Holder ............................................................................................................................ 7
Attaching the Fork Arm to the Tripod......................................................................................................................... 7
Attaching the Telescope to the Fork Arm ................................................................................................................... 7
The Star Diagonal ....................................................................................................................................................... 7
The Eyepiece............................................................................................................................................................... 8
Focusing...................................................................................................................................................................... 8
The Star Pointer Finderscope...................................................................................................................................... 8
Star Pointer Installation............................................................................................................................................... 9
Star Pointer Operation................................................................................................................................................. 9
Attaching the Hand Control ...................................................................................................................................... 10
Powering the NexStar ............................................................................................................................................... 10
HAND CONTROL ......................................................................................................................................................... 11
The Hand Control ..................................................................................................................................................... 11
Hand Control Operation................................................................................................................................................ 12
Alignment Procedure ................................................................................................................................................ 13
Sky Align.................................................................................................................................................................. 13
Auto Two-Star Align ................................................................................................................................................ 15
Two Star Alignment.................................................................................................................................................. 15
One-Star Align.......................................................................................................................................................... 16
Solar System Align ................................................................................................................................................... 16
NexStar Re-Alignment.............................................................................................................................................. 17
Object Catalog .............................................................................................................................................................. 17
Selecting an Object ................................................................................................................................................... 17
Slewing to an Object................................................................................................................................................. 18
Finding Planets ......................................................................................................................................................... 18
Tour Mode ................................................................................................................................................................ 18
Constellation Tour .................................................................................................................................................... 18
Direction Buttons.......................................................................................................................................................... 19
Rate Button ............................................................................................................................................................... 19
Set Up Procedures......................................................................................................................................................... 19
Tracking Mode.......................................................................................................................................................... 19
Tracking Rate............................................................................................................................................................ 20
View Time-Site......................................................................................................................................................... 20
User Defined Objects................................................................................................................................................ 20
Get R.A./DEC. .......................................................................................................................................................... 20
Goto R.A./DEC......................................................................................................................................................... 20
Identify...................................................................................................................................................................... 21
Scope Setup Features .................................................................................................................................................... 21
Anti-backlash ............................................................................................................................................................ 21
Slew Limits............................................................................................................................................................... 21
Filter Limits .............................................................................................................................................................. 21
Direction Buttons...................................................................................................................................................... 22
Goto Approach.......................................................................................................................................................... 22
Cordwrap .................................................................................................................................................................. 22
Utility Features ............................................................................................................................................................. 22
GPS On/Off............................................................................................................................................................... 22
Light Control............................................................................................................................................................. 22
Factory Setting.......................................................................................................................................................... 22
Version...................................................................................................................................................................... 22
Get Axis Position ...................................................................................................................................................... 22
Goto Axis Position.................................................................................................................................................... 22
Hibernate................................................................................................................................................................... 22
Sun Menu.................................................................................................................................................................. 23

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Scrolling Menu ......................................................................................................................................................... 23
Calibrate Goto........................................................................................................................................................... 23
Set Mount Position.................................................................................................................................................... 23
TELESCOPE BASICS ................................................................................................................................................... 25
Focusing.................................................................................................................................................................... 25
Image Orientation ..................................................................................................................................................... 25
Calculating Magnification......................................................................................................................................... 26
Determining Field of View ....................................................................................................................................... 26
General Observing Hints........................................................................................................................................... 26
CELESTIAL OBSERVING........................................................................................................................................... 27
Observing the Moon ................................................................................................................................................. 27
Lunar Observing Hints.............................................................................................................................................. 27
Observing the Planets................................................................................................................................................ 27
Planetary Observing Hints ........................................................................................................................................ 27
Observing the Sun..................................................................................................................................................... 27
Solar Observing Hints............................................................................................................................................... 28
Observing Deep Sky Objects .................................................................................................................................... 28
Seeing Conditions ..................................................................................................................................................... 28
Transparency............................................................................................................................................................. 28
Sky Illumination........................................................................................................................................................ 28
Seeing ....................................................................................................................................................................... 29
TELESCOPE MAINTENANCE ................................................................................................................................... 30
Care and Cleaning of the Optics ................................................................................................................................... 30
Collimation ................................................................................................................................................................... 30
OPTIONAL ACCESSORIES....................................................................................................................................... 32
APPENDIX A - TECHNICAL SPECIFICATIONS.................................................................................................. 34
APPENDIX B – GLOSSARY OF TERMS................................................................................................................... 35
APPENDIX C – RS-232 CONNECTION ..................................................................................................................... 38
APPENDIX D – TIME ZONE MAPS........................................................................................................................... 39
SKY MAPS...................................................................................................................................................................... 41

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Congratulations on your purchase of the Celestron NexStar telescope! The NexStar ushers in a whole new
generation of computer automated technology. Simple and friendly to use, the NexStar is up and running after
locating just three bright celestial objects. It’s the perfect combination of power and portability. If you are new to
astronomy, you may wish to start off by using the NexStar's built-in Sky Tour feature, which commands the
NexStar to find the most interesting objects in the sky and automatically slews to each one. Or if you are more
experienced, you will appreciate the comprehensive database of over 4,000 objects, including customized lists of
all the best deep-sky objects, planets, bright double stars. No matter at what level you are starting out, the NexStar
will unfold for you and your friends all the wonders of the Universe.
Some of the many standard features of the NexStar include:
yIncredible 3°/second slew speed.
yFully enclosed motors and optical encoders for position location.
yComputerized hand controller with 4,000 object database.
yStorage for programmable user defined objects; and
yMany other high performance features!
The NexStar’s deluxe features combined with Celestron’s legendary optical standards give amateur astronomers
one of the most sophisticated and easy to use telescopes available on the market today.
Take time to read through this manual before embarking on your journey through the Universe. It may take a few
observing sessions to become familiar with your NexStar, so you should keep this manual handy until you have
fully mastered your telescope’s operation. The NexStar hand control has built-in instructions to guide you
through all the alignment procedures needed to have the telescope up and running in minutes. Use this manual in
conjunction with the on-screen instructions provided by the hand control. The manual gives detailed information
regarding each step as well as needed reference material and helpful hints guaranteed to make your observing
experience as simple and pleasurable as possible.
Your NexStar telescope is designed to give you years of fun and rewarding observations. However, there are a few
things to consider before using your telescope that will ensure your safety and protect your equipment.
Warning
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.
Never use your telescope to project an image of the sun onto any surface. Internal heat build-up can
damage the telescope and any accessories attached to it.
Never use an eyepiece solar filter or a Herschel wedge. Internal heat build-up inside the telescope
can cause these devices to crack or break, allowing unfiltered sunlight to pass through to the eye.
Never leave the telescope unsupervised, either when children are present or adults who may not be
familiar with the correct operating procedures of your telescope.

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1 Corrector Lens 7 Tripod Leg Extension Clamp
2 Fork Arm 8 Hand Control
3 Battery Compartment 9 Star Diagonal
4 Tripod Coupling Screw 10 Eyepiece
5 Tripod 11 Star Pointer Finderscope
6 Accessory Tray 12 Telescope Tube
The NexStar SLT Telescope
(NexStar 127MAK Shown)
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The NexStar comes partially assembled and can be operational in a matter of minutes. The NexStar is conveniently
packaged in one reusable shipping carton that contains the following accessories:
y25mm and 9mm Eyepieces – 1¼"
y1¼" Star Diagonal
yStar Pointer Finderscope and Mounting Bracket
yDeluxe Accessory Tray
yThe Sky™ X Astronomy Software
yNSOL Telescope Control Software
yNexStar Hand Control w/ Object Database
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As ss se em mb bl li in ng g t th he e N Ne ex xS St ta ar r
Your NexStar comes in three major sections: the optical tube, the fork arm and the tripod. These sections can be
attached in seconds using the quick release coupling screw located under the tripod mounting platform and the dovetail
mounting clamp located on the inside of the fork arm. To begin, remove all of the accessories from their individual
boxes. Remember to save all of the containers so that they can be used to transport the telescope. Before attaching the
visual accessories, the telescope tube should be mounted to its tripod. First, install the accessory tray onto the tripod
legs:
1. Remove the tripod from the box and spread the legs apart
until the center leg brace is fully extended.
2. Locate the accessory tray, and place it on top of the tripod
center support brace in between the tripod legs (see figure 2-1).
3. Rotate the accessory tray so that the central hole in the tray
slides over the flange post in the center of the support
bracket.
4. Finally, rotate the tray so that the locking tabs slide under
the locking clips on support bracket. You will here the tray
snap into place.
It is a good idea to level the tripod and adjust the height of the tripod legs before attaching the fork arm and tube. Minor
adjustments can be made later. To adjust the height of the tripod legs:
1. Loosen the tripod leg locking bolt located on the side of each leg.
2. Slide the inner portion of each leg down 6" to 8" inches.
3. Adjust the tripod height until the bubble level on the tripod leg is centered.
4. Tighten the tripod locking bolts to hold each leg in place.
Figure 2-1
Flange Post
Locking Tabs
Locking
Clips
Bubble
Level
Figure 2-2

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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
The NexStar comes with a snap-on hand control holder that conveniently attaches to any of
the tripod legs. To attach the hand control holder simply position the holder with the square
plastic tab facing up and push against the tripod leg until it snaps in to place.
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At tt ta ac ch hi in ng g t th he e F Fo or rk k A Ar rm m t to o t th he e T Tr ri ip po od d
With the tripod properly assembled, the telescope tube and fork arm can easily be attached
using the quick release coupling screw located underneath the tripod mounting platform:
1. Place the fork arm base inside the tripod mounting platform.
2. Thread the coupling screw into the hole at the bottom of the fork arm base and hand
tighten.
Figure 2-4
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At tt ta ac ch hi in ng g t th he e T Te el le es sc co op pe e t to o t th he e F Fo or rk k A Ar rm m
Your telescope optical tube has a built on dovetail mounting bar used to attach the tube to the fork arm. To attach the telescope
tube:
1. Loosen the tube clamp tightening knob.
2. Slide the dovetail mounting bar of the telescope tube into the fork arm clamp.
Make sure that the logo on the side of the tube is right side up when the tube is
aligned with the fork arm.
3. Tighten the tube clamp knob by hand to secure the tube to the fork arm.
Your NexStar is fully assembled and is ready to attach the accessories.
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Th he e S St ta ar r D Di ia ag go on na al l
The star diagonal diverts the light at a right angle from the light path of the telescope.
For astronomical observing, this allows you to observe in positions that are more
comfortable than if you were to look straight through. To attach the star diagonal:
1. Turn the thumbscrew on the eyepiece adapter at the end of the focuser barrel until it no
longer extends into (i.e., obstructs) the inner diameter of the focus barrel. Remove the protective dust cap from the focuser
barrel.
2. Slide the chrome portion of the star diagonal into the eyepiece adapter.
3. Tighten the thumbscrew on the eyepiece adapter to hold the star diagonal in place.
If you wish to change the orientation of the star diagonal, loosen the thumbscrew on the eyepiece adapter until the star diagonal
rotates freely. Rotate the diagonal to the desired position and tighten the thumbscrew.
Figure 2-3
Tube Clamp
Tightening Knob
Dovetail
Mounting Bar
Figure 2-5
Fork Arm
Base
Tripod Mounting
Platform
Coupling
Screw

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Th he e E Ey ye ep pi ie ec ce e
The eyepiece, is the optical element that magnifies the image focused by the telescope. The eyepiece fits directly into the star
diagonal. To install the eyepiece:
1. Loosen the thumbscrew on the star diagonal so it does not obstruct the inner
diameter of the eyepiece end of the diagonal. Remove the protective dust cap
from the star diagonal's barrel.
2. Slide the chrome portion of the low power 25mm eyepiece into the star
diagonal.
3. Tighten the thumbscrew to hold the eyepiece in place.
To remove the eyepiece, loosen the thumbscrew on the star diagonal and slide the
eyepiece out.
Eyepieces are commonly referred to by focal length and barrel diameter.
The focal length of each eyepiece is printed on the eyepiece barrel. The longer
the focal length (i.e., the larger the number) the lower the eyepiece power or
magnification; and the shorter the focal length (i.e., the smaller the number) the
higher the magnification. Generally, you will use low-to-moderate power when viewing. For more information on how to
determine power, see the section on “Calculating Magnification.”
Barrel diameter is the diameter of the barrel that slides into the star diagonal or focuser. The NexStar uses eyepieces with a
standard 1-1/4" barrel diameter.
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Fo oc cu us si in ng g
The NexStar's focusing mechanism controls the primary mirror which is mounted on a ring that slides back and forth on the primary
baffle tube. The focusing knob, which moves the primary mirror, is on the rear cell of the telescope just below the star diagonal and
eyepiece. Turn the focusing knob until the image is sharp. If the knob will not turn, it has reached the end of its travel on the
focusing mechanism. Turn the knob in the opposite direction until the image is sharp. Once an image is in focus, turn the knob
clockwise to focus on a closer object and counterclockwise for a more distant object. A single turn of the focusing knob moves the
primary mirror only slightly. Therefore, it will take many turns (about 25) to go from close focus (approximately 20 feet) to
infinity.
For astronomical viewing, out of focus star images are very diffuse, making them difficult to see. If you turn the focus knob too
quickly, you can go right through focus without seeing the image. To avoid this problem, your first astronomical target should be a
bright object (like the Moon or a planet) so that the image is visible even when out of focus. Critical focusing is best accomplished
when the focusing knob is turned in such a manner that the mirror moves against the pull of gravity. In doing so, any mirror shift is
minimized. For astronomical observing, both visually and photographically, this is done by turning the focus knob
counterclockwise.
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Th he e S St ta ar r P Po oi in nt te er r F Fi in nd de er rs sc co op pe e
The Star Pointer is the quickest and easiest way to point your telescope exactly at a desired object in the sky. It's like having a laser
pointer that you can shine directly onto the night sky. The Star Pointer is a zero magnification pointing tool that uses a coated glass
window to superimpose the image of a small red dot onto the night sky. While keeping both eyes open when looking through the
Star Pointer, simply move your telescope until the red dot, seen through the Star Pointer, merges with the object as seen with your
unaided eye. The red dot is produced by a light-emitting diode (LED); it is not a laser beam and will not damage the glass window
or your eye. The Star Pointer comes equipped with a variable brightness control, two axes alignment control and mounting brackets.
Before the Star Pointer is ready to be used, it must be attached to the telescope tube and properly aligned:
Figure 2-6
Visual accessories for the NexStar 90 & 127
MAK models
Eyepiece
Star Pointer
Finderscope
Star
Diagonal
Focuser Knob

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St ta ar r P Po oi in nt te er r I In ns st ta al ll la at ti io on n
1. Slide the Star Pointer bracket into the dovetail mounting platform on top of the
focuser assembly (see figure 2-9).
2. Orient the Star Pointer so that the sight tube is facing towards the front of the tube.
3. Secure the Star Pointer bracket by tightening the thumb screw on the mounting
platform.
Star Pointer Operation
The star pointer is powered by a long life 3-volt lithium battery (#CR2032) located
underneath the front portion of the Star Pointer. Like all finderscopes, the Star Pointer
must be properly aligned with the main telescope before it can be used. This is a simple
process using the azimuth and altitude control knobs located on the side and bottom of
the Star Pointer. The alignment procedure is best done at night since the LED dot will
be difficult to see during the day.
1. Before using the StarPointer, you must first remove the protective plastic cover over the battery (see figure 2-10).
2. To turn on the Star Pointer, rotate the variable brightness control (see figure 2-8) clockwise until you here a "click".
To increase the brightness level of the red dot, continue rotating the control knob about 180º until it stops.
3. Locate a bright star or planet and center it in a low power eyepiece in the main telescope.
4. With both eyes open, look through the glass window at the alignment star. If the Star Pointer is perfectly aligned, you will
see the red LED dot overlap the alignment star. If the Star Pointer is not aligned, take notice of where the red dot is
relative to the bright star.
5. Without moving the main telescope, turn the Star Pointer's azimuth and altitude alignment controls (see figure 2-8) until
the red dot is directly over the alignment object.
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Fi ig gu ur re e 2 2- -8 8
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Th he e S St ta ar r P Po oi in nt te er r F Fi in nd de er rs sc co op pe e w wi it th h B Br ra ac ck
ke et t
Dovetail
Tightening
Screw
Azimuth
Adjustment
Control
ON/OFF
Brightness Control
Sight Tube
Dovetail Mount
Battery
Compartment
(not shown)
Altitude
Adjustment
Control
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Fi ig gu ur re e 2 2- -9 9
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In ns st ta al ll li in ng g t th he e S St ta ar r P Po oi in nt te er r
Mounting
Platform
Thumb Screw

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If the LED dot is brighter than the alignment star, it may make it difficult to see the star. Turn the brightness control
counterclockwise, until the red dot is the same brightness as the alignment star. This will make it easier to get an accurate
alignment. The Star Pointer is now ready to be used.
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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
The NexStar SLT hand control has a phone jack type connector at the end of its cord. Plug the phone jack connector into the outlet
at the base of the telescope’s fork arm. Push the connector into the outlet until it clicks into place and place the hand control into its
holder as described previously in the Assembly section of the manual.
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Po ow we er ri in ng g t th he e N Ne ex xS St ta ar r
The NexStar SLT can be powered by 8 user supplied AA size alkaline batteries or an optional 12 V AC adapter. To install batteries
into the NexStar:
1. Squeeze the tabs on both sides of the battery compartment cover while lifting
upward.
2. Insert 8 AA batteries in to battery compartment holders.
3. Place the battery compartment cover over the batteries and push down until the
cover snaps in place.
4. Flip the power switch to the “On” position. The light on the power button should
come on.
In case of a loss of power, the optical tube can be moved by hand. However, when
powered on, the telescope should always be controlled via the hand control.
The NexStar will lose its star alignment if moved by hand when powered on.
Figure 2-12
The NexStar SLT Outlets
ON/Off Switch
Auxiliary Port
Hand
Control Port
12 V Power
Outlet
Figure 2-13
Removing the Battery Compartment
Cover
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Fi ig gu ur re e 2 2- -1 11 1
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Al li ig gn ni in ng g t th he e S St ta ar rP Po oi in nt te er r
Azimuth
adjustment
Knob
Red
Alignment
Dot
Battery
Protective
Cover
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Fi ig gu ur re e 2 2- -1 10 0
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Ba at tt te er ry y C Co om mp pa ar rt tm me en nt t

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Th he e H Ha an nd d C Co on nt tr ro ol l
The NexStar SLT's hand controller is designed to give you instant access to all the functions the NexStar has to offer.
With automatic slewing to over 4,000 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
NexStar SLT 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 NexStar to use a selected star or object as an alignment position.
3. Direction Keys: Allows complete control of the NexStar in any direction. Use the direction keys to center objects in
the StarPointer finderscope and eyepiece.
4. Catalog Keys: The NexStar has a key on the hand control to allow direct access to each of the catalogs in its 4,000+
object database. The NexStar contains the following catalogs in its database:
Messier – Complete list of all Messier objects.
NGC – Many of the brightest deep sky objects from 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 and Sun.
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 NexStar 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 Alphabetical listing of the most visually stunning double, triple and
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.

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5. Info:Displays coordinates and useful information about objects selected from the NexStar database.
6. Tour: Activates the tour mode, which seeks out all the best objects for a given month and automatically slews the
NexStar to those objects.
7. Enter: Pressing Enter allows you to select any of the NexStar functions, accept entered parameters and slew the
telescope to displayed objects.
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 rate 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 symbol on the right side of
the LCD indicates that the scroll keys can be used to view additional information.
11. Rate: Instantly changes the rate of speed of the motors when the direction buttons are pressed.
12. RS-232 Jack: Allows use with a computer and software programs for point and click slewing capability.
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Ha an nd d C Co on nt tr ro ol l O Op pe er ra at ti io on n
This section describes the basic hand control procedures needed to operate the NexStar. 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 utility functions such as adjusting the telescopes slew limits and backlash
compensation.
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Figure 3-1
The NexStar Hand Control

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A
Al li ig gn nm me en nt t P Pr ro oc ce ed du ur re e
In order for the NexStar to accurately point to objects in the sky, it must first be aligned to 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 the NexStar with the sky depending on what information the user
is able to provide: SkyAlign uses your current date, time and city to create an accurate model of the sky. Then the
user can simply point the telescope to any three bright celestial objects to accurately align the telescope with the sky.
Auto Two-Star Align will ask the user to choose and center the first alignment star, then the NexStar will
automatically select and slew to a second star for alignment. Two-Star Alignment requires the user to identify and
manually slew the telescope to the two alignment stars. One-Star Align is the same as Two-Star Align however only
requires you to align to one known star. Although not as accurate as the other alignment methods, One-Star Align is
the quickest way to find and track bright planets and objects in Altazimuth mode. Finally, Solar System Align will
display a list of visible daytime objects (planets and the moon) available to align the telescope. Each alignment
method is discussed in detail below.
"Altazimuth" or "Alt-Az" refers to a type of mounting that allows a telescope to move in both altitude (up and down)
and azimuth (left and right) with respect to the ground. This is the simplest form of mounting in which the telescope
is attached directly to a tripod.
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Sk ky y A Al li ig gn n
Sky Align is the easiest way to get your NexStar aligned and ready to observe. Even if you do not know a single star
in the sky, the NexStar will have you aligned in minutes by asking for basic information like the date, time and
location. Then you simply need to aim the telescope to any three bright celestial objects in the sky. Since Sky Align
requires no knowledge of the night sky it is not necessary to know the name of the stars at which you are aiming.
You may even select a planet or the moon. The NexStar is then ready to start finding and tracking any of the objects
in its 4,000+ object database. Before the telescope is ready to be aligned, it should be set up in an outside location
with all accessories (eyepiece, diagonal and finderscope) attached and lens cover removed as described in the
Assembly section of the manual. To begin Sky Align:
1. Power on the NexStar by flipping the switch located on the side of the fork arm, to the "on" position. Once
turned on the hand control display will say
NexStar SLT
. Press ENTER to choose Sky Align. Pressing the
ALIGN key will bypass the other alignment options and the scrolling text and automatically begins Sky Align.
2. Once Sky Align has been selected, the hand control will display “Enter if OK”, “Undo to edit” and “Saved Site”.
The bottom line of the LCD will display either the current time or the time when you last used the telescope.
Since this is your first time using the NexStar, press UNDO to enter current time/site information.
The hand control display will then ask for the following information:
Location - The NexStar 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 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 States
is displayed. For international locations,
use the Up or Down scroll key to select
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.
Definition

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Time - Enter the current time for your area. You can enter either the local time (i.e. 8:00), 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. For time zone information, refer to the Time Zone map in the appendix of this manual.
Date - Enter the month, day and year of your observing session. The display will read: mm/dd/yy.
yIf the wrong information has been input into the hand control, the UNDO button will act as a backspace
allowing the user to re-enter information.
yThe next time that your NexStar is aligned, the hand control will automatically display the last location
(either a city or longitude/latitude) that was entered. Press ENTER to accept these parameters if they still
apply. Pressing the UNDO button will allow you to go back and select a new city location or
longitude/latitude.
3. Use the arrow buttons on the hand control to slew (move) the telescope towards any bright celestial object in
the sky. Align the object with the red dot of the finderscope and press ENTER.
4. If the finderscope has been properly aligned with the telescope tube, the alignment star should now be
visible inside the field of view of the eyepiece. The hand control will ask that you center the bright
alignment star in the center of the eyepiece and press the ALIGN button. This will accept the star as the first
alignment position. (There is no need to adjust the slewing rate of the motors after each alignment step.
The NexStar automatically selects the best slewing rate for aligning objects in both the finderscope and the
eyepiece).
5. For the second alignment object, choose a bright star or planet as far as possible from the first alignment
object. Once again use the arrow button to center the object in the finderscope and press ENTER.
Then once centered in the eyepiece press the ALIGN button.
6. Repeat the process for the third alignment star. When the telescope has been aligned to the final stars, the
display will read "
Match Confirmed".
Press UNDO to display the names of the three bright objects
you aligned to, or press ENTER to accept these three objects for alignment. You are now ready to find your
first object.
Tips for Using Sky Align
Remember the following alignment guidelines to make using Sky Align as simple and accurate as possible.
yBe sure to level the tripod before you begin alignment. The time/site information along with a level
tripod will help the telescope better predict the available bright stars and planets that are above the horizon.
yRemember to select alignment stars that are as far apart in the sky as possible. For best results make sure
that the third alignment star does not lie in a straight line between the first two stars. This may result in a
failed alignment.
yDon’t worry about confusing planets for stars when selecting alignment objects. SkyAlign works with the
four brightest planets (Venus, Jupiter, Saturn and Mars) as well as the Moon. In addition to the planets, the
hand control has over 80 bright alignment stars to choose from (down to 2.5 magnitude).
yRarely SkyAlign will not be able to determine what three alignment objects were centered. This sometimes
happens when a bright planet or the Moon passes near one of the brighter stars. In situations like these it is
best to try to avoid aligning to either object if possible.
yBe sure to center the objects with the same final movements as the direction of the GoTo Approach.
For example, if the scope normally finishes a GoTo with the front of the scope moving right and up, you
should center all three alignment objects in the eyepiece using the right and up arrow buttons (the up/down
arrows reverse at slew rates of 6 or lower). Approaching the star from this direction when looking through
the eyepiece will eliminate much of the backlash between the gears and assure the most accurate alignment
possible.
Helpful
Hints

15
A
Au ut to o T Tw wo o- -S St ta ar r A Al li ig gn n
As with Sky Align, Auto Two-Star Align requires you to enter all the necessary time/site information as before. Once this
information is entered, NexStar will prompt you to select and point the telescope at one known star in the sky.
The NexStar now has all the information it needs to automatically choose a second star that will assure the best possible
alignment. Once selected the telescope will automatically slew to that second alignment star to complete the alignment.
With the NexStar set up outside with all accessories attached and the tripod leveled, follow the steps below to align the
telescope:
1. Once the NexStar is powered on, Press ENTER to begin alignment.
2. Use the Up and Down scroll keys (10) to select Auto Two-Star Align and press ENTER.
3. The hand control will display the last time and location information that was entered into the hand control. Use the Up
and Down buttons to scroll through the information. Press ENTER to accept the current information or press UNDO
to manually edit the information (see Sky Align section for detailed instruction on entering time/site information).
4. The display will now prompt you to select a bright star from the displayed list on the hand control. Use Up and Down
buttons (6 and 9 on the keypad) to scroll to the desired star and then press ENTER.
5. Use the arrow buttons to slew the telescope to the star you selected. Center the star in the finderscope and press
ENTER. Finally, center the star in the eyepiece and press ALIGN.
6. Based on this information, the NexStar will automatically display the most suitable second alignment star that is
above the horizon. Press ENTER to automatically slew the telescope to the displayed star. If for some reason you do
not wish to select this star (perhaps it is behind a tree or building), you can either:
yPress the UNDO button to display the next most suitable star for alignment.
yUse the UP and DOWN scroll buttons to manually select any star you wish from the entire list of available stars.
Once finished slewing, the display will ask you to use the arrow buttons to align the selected star with the red dot of the
finderscope. Once centered in the finder, press ENTER. 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 second alignment star. When the
telescope has been aligned to both stars the display will read
Align Success
, and you are now ready to find your first
object.
T
Tw wo o S St ta ar r A Al li ig gn nm me en nt t
With the two-star alignment method, the NexStar requires the user to know the positions of two bright stars in order to
accurately align the telescope with the sky and begin finding objects. Here is an overview of the two-star alignment
procedure:
1. Once the NexStar is powered on, use the Up and Down scroll keys (10) to select Two-Star Align, and press ENTER.
2. Press ENTER to accept the time/site information displayed on the display, or press UNDO to enter new information.
3. The SELECT STAR 1 message will appear in the top row of the display. Use the Up and Down scroll keys (10) to
select the star you wish to use for the first alignment star. Press ENTER.
4. NexStar then asks you to center in the eyepiece the alignment star you selected. Use the direction arrow buttons to
slew the telescope to the alignment star and carefully center the star in the finderscope. Press ENTER when centered.
5. Then, center the star in the eyepiece and press ALIGN.
In order to accurately center the alignment star in the eyepiece, you may wish to decrease the slew rate of the motors
for fine centering. This is done by pressing the RATE key (11) on the hand controller then selecting the number that
corresponds to the speed you desire. (9 = fastest, 1 = slowest).
6. NexStar will then ask you to select and center a second alignment star and press the ALIGN key. It is best to choose
alignment stars that are a good distance away from one another. Stars that are at least 40º to 60º apart from each other
will give you a more accurate alignment than stars that are close to each other.
Once the second star alignment is completed properly, the display will read
Align Successful
, and you should hear
the tracking motors turn-on and begin to track.
Helpful
Hint

16
O
On ne e- -S St ta ar r A Al li ig gn n
One-Star Align requires you to input all the same information as you would for the Two-Star Align procedure. However,
instead of slewing to two alignment stars for centering and alignment, the NexStar uses only one star to model 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 NexStar the information needed to track objects in altazimuth in any part of the sky. One-Star 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 One-Star Align:
1. Select One-Star Align from the alignment options.
2. Press ENTER to accept the time/site information displayed on the display, or press UNDO to enter new information.
3. The SELECT STAR 1 message will appear in the top row of the display. Use the Up and Down scroll keys (10) to
select the star you wish to use for the first alignment star. Press ENTER.
4. NexStar then asks you to center in the eyepiece the alignment star you selected. Use the direction arrow buttons to
slew the telescope to the alignment star and carefully center the star in the finderscope. Press ENTER when centered.
5. Then, center the star in the eyepiece and press ALIGN.
6. Once in position, the NexStar will model the sky based on this information and display
Align Successful
.
Note: Once a One-Star Alignment has been done, you can use the Re-alignment feature (later in this section ) to improve
your telescope’s pointing accuracy.
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 night time 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. Press ENTER to accept the time/site information displayed on the display, or press UNDO to enter new information.
3. 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.
4. NexStar then asks you to center in the eyepiece the alignment object you selected. Use the direction arrow buttons to
slew the telescope to the alignment object and carefully center it in the finderscope. Press ENTER when centered.
5. Then, center the object in the eyepiece and press ALIGN.
Once in position, the NexStar will model the sky based on this information and display
Align Successful
.
Tips for Using Solar System Align
yFor 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 “NexStar SLT”
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 use the Re-Align feature as described below.

17
N
Ne ex xS St ta ar r R Re e- -A Al li ig gn nm me en nt t
The NexStar has a re-alignment feature which allows you to replace either of the original alignment stars with a new star
or celestial object. This can be useful in several situations:
yIf you are observing over a period of a few hours, you may notice that your original two alignment stars have drifted
towards the west considerably. (Remember that the stars are moving at a rate of 15º every hour). Aligning on a new star
that is in the eastern part of the sky will improve your pointing accuracy, especially on objects in that part of the sky.
yIf you have aligned your telescope using the One-star align method, you can use re-align to align to an additional
object 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. Carefully center the object in the eyepiece.
3. Once centered, press the UNDO button until you are at the main menu.
4. With NexStar SLT displayed, press the ALIGN key on the hand control.
5. The display will then ask you which alignment star you want to replace.
6. 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. If you have used one
of the single object alignment methods then it is always best to replace the object that is “unassigned” with an actual
object.
7. Press ALIGN to make the change.
O
Ob bj je ec ct t C Ca at ta al lo og g
S
Se el le ec ct ti in ng g a an n O Ob bj je ec ct t
Now that the telescope is properly aligned, you can choose an object from any of the catalogs in the NexStar’s database.
The hand control has a key designated for each of the catalogs in its database. There are two ways to select objects from
the database; scrolling through the named object lists and entering object numbers:
y
Pressing the LIST key on the hand control will access all objects in the database that have common names or types.
Each list is broken down into the following categories: Named Stars, Named Object, Double Stars, Variable Stars and
Asterisms. Selecting any one of these options will display an alpha-numeric listing of the objects under that list.
Pressing the Up and Down keys (10) allows you to scroll through the catalog to the desired object.
y
Pressing any of the catalog keys (M, CALD, NGC, or STAR) will display a blinking cursor below the name of the
catalog chosen. Use the numeric key pad to enter the number of any object within these standardized catalogs.
For example, to find the Orion Nebula, press the "M" key and enter "042".
y
Pressing the PLANET button will allow you to use the UP and DOWN arrow keys to scroll through and select the
eight planets as well as the moon.
When scrolling through a long list of objects, holding down either the Up or Down key will allow you to scroll through the
catalog at a rapid speed.
When entering the number for a SAO star, you are only required to enter the first four digits of the objects six digit SAO
number. Once the first four digits are entered, the hand control will automatically list all the available SAO objects
beginning with those numbers. This allows you to scroll through only the SAO stars in the database. For example, in
searching for the SAO star 40186 (Capella), the first four digits would be "0401". Entering this number will display the
closest match from the SAO stars available in the database. From there you can scroll down the list and select the desired
object.

18
S
Sl le ew wi in ng g t to o a an n O Ob bj je ec ct t
Once the desired object is displayed on the hand control screen, you have two options:
y
Press the INFO Key. This will give you useful information about the selected object such as magnitude,
constellation and fascinating facts about many of the objects.
y
Press the ENTER Key. This will automatically slew the telescope to the coordinates of the object. While the
telescope is slewing to the object, the user can still access many of the hand control functions (such as displaying
information about the object).
If you slew to an object that is below the horizon, NexStar will notify you by displaying a message reminding you that you
have selected an object outside of your slew limits (see Slew Limits in the Scope Setup section of the manual).
Press UNDO to go back and select a new object. Press ENTER to ignore the message and continue the slew. The NexStar
hand control will only display objects that are below the horizon if the Filter Limits are set below 0º in altitude. See Filter
Limits in the Utility Feature section of the manual for more information on setting the filter limits.
Caution: Never slew the telescope when someone is looking into the eyepiece. The telescope can move at fast slew
speeds and may hit an observer in the eye.
Object information can be obtained without having to do a star alignment. After the telescope is powered on, pressing any
of the catalog keys allows you to scroll through object lists or enter catalog numbers and view the information about the
object as described above.
F
Fi in nd di in ng g P Pl la an ne et ts s
The NexStar can locate all 8 of our solar systems planets plus the Sun and Moon. However, the hand control will only
display the solar system objects that are above the horizon (or within its filter limits). To locate the planets, press the
PLANET key on the hand control. The hand control will display all solar system objects that are above the horizon:
yUse the Up and Down keys to select the planet that you wish to observe.
yPress INFO to access information on the displayed planet.
yPress ENTER to slew to the displayed planet.
To allow the Sun to be displayed as an option in the database, see Sun Menu in the Utilities section of the manual.
T
To ou ur r M Mo od de e
The NexStar includes a tour feature which automatically allows the user to choose from a list of interesting objects based
on the date and time in which you are observing. The automatic tour will display only those objects that are within your set
filter limits. To activate the Tour mode, press the TOUR key on the hand control. The NexStar will display the best objects
to observe that are currently in the sky.
yTo see information and data about the displayed object, press the INFO key.
yTo slew to the object displayed, press ENTER.
yTo see the next tour object, press the Down key.
C
Co on ns st te el ll la at ti io on n T To ou ur r
In addition to the Tour Mode, the NexStar telescope has a Constellation Tour that allows the user to take a tour of all the
best objects within a particular constellation. Selecting Constellation from the LIST menu will display all the
constellation names that are above the user defined horizon (filter limits). Once a constellation is selected, you can choose
from any of the database object catalogs to produce a list of all the available objects in that constellation.
yTo see information and data about the displayed object, press the INFO key.
yTo slew to the object displayed, press ENTER.
yTo see the next tour object, press the Up key.

19
D
Di ir re ec ct ti io on n B Bu ut tt to on ns s
The NexStar has four direction buttons in the center of the hand control which controls the telescope motion in altitude
(up and down) and azimuth (left and right). The telescope can be controlled at nine different speed rates.
1 = 2x 6 = 64x
2 = 4x 7 = 1º / sec
3 = 8x 8 = 2º / sec
4 = 16x 9 = 3º / sec
5 = 32x
R
Ra at te e B Bu ut tt to on n
Pressing the RATE key (11) allows you to instantly change the speed rate of the motors from high speed slew rate to
precise guiding rate or anywhere in between. Each rate corresponds to a number on the hand controller key pad.
The number 9 is the fastest rate (approximately 4º per second, depending on power source) and is used for slewing
between objects and locating alignment stars. The number 1 on the hand control is the slowest rate (2x sidereal) and can
be used for accurate centering of objects in the eyepiece. To change the speed rate of the motors:
y
Press the RATE key on the hand control. The LCD will display the current speed rate.
y
Press the number on the hand control that corresponds to the desired speed.
The hand control has a "double button" feature that allows you to instantly speed up the motors without having to choose a
speed rate. To use this feature, simply press the arrow button that corresponds to the direction that you want to move the
telescope. While holding that button down, press the opposite directional button. This will increase the speed to the
maximum slew rate.
When using the Up and Down buttons on the NexStar 60 and 80, the slower slew rates (6 and lower) move the motors in
the opposite direction than the faster slew rates (7- 9). This is done so that an object will move in the appropriate direction
when looking into the eyepiece (i.e. pressing the up arrow button will move the star upwards in the field of view of the
eyepiece). However, if any of the slower slew rates (rate 6 and below) are used to center an object in the Star Pointer, you
may need to press the opposite directional button to make the telescope move in the correct direction.
S
Se et t U Up p P Pr ro oc ce ed du ur re es s
The NexStar contains many user defined setup functions designed to give the user control over the telescope's many
advanced features. All of the set up and utility features can be accessed by pressing the MENU key and scrolling through
the options:
Tracking Mode - Once the NexStar is aligned the tracking motors will automatically turn on and begin tracking the
sky. However, the tracking can be turned off for terrestrial use:
Alt-Az This is the default tracking rate and is used when the telescope has been
properly aligned.
EQ North Used to track the sky when the telescope is polar aligned using an equatorial
wedge in the Northern Hemisphere.
EQ South Used to track the sky when the telescope is polar aligned using an equatorial
wedge in the Southern Hemisphere.
Off When using the telescope for terrestrial (land) observation the tracking can
be turned off so that the telescope never moves.
Note: EQ North and EQ South tracking modes are only needed with telescopes that can be polar aligned.
The NexStar SLT series are exclusively Alt-Az mounted telescopes and do not require equatorial tracking.
Nine available slew speeds

20
Tracking Rate - In addition to being able to move the telescope with the hand control buttons, the NexStar will
continually track a celestial object as it moves across the night sky. The tracking rate can be changed depending on what
type of object is being observed:
Sidereal This rate compensates for the rotation of the earth by moving the telescope at
the same rate as the rotation of the earth, but in the opposite direction. When
tracking in Alt-Az mode, the telescope must make corrections in both altitude
and azimuth.
Lunar Used for tracking the moon when observing the lunar landscape.
Solar Used for tracking the Sun when solar observing using a proper solar filter.
View Time-Site -View Time-Site will display the last saved time and longitude/latitude entered in the hand control.
User Defined Objects: The NexStar can store up to 50 different user defined objects in its memory.
The objects can be daytime land objects or an interesting celestial object that you
discover that is not included in the regular database. There are several ways to
save an object to memory depending on what type of object it is:
Save Sky Object: The NexStar stores celestial objects to its database by saving its right ascension
and declination in the sky. This way the same object can be found each time the
telescope is aligned. Once a desired object is centered in the eyepiece, simply
scroll to the "
Save Sky Obj"
command and press ENTER. The display will
ask you to enter a number between 1-25 to identify the object. Press ENTER
again to save this object to the database.
Save Database (Db)
Object:
This feature allows you to create your own custom tour of database objects by
allowing you to record the current position of the telescope and save the name of
the object by selecting it from any one of the database catalogs. These objects
then can be accessed by selecting GoTo Sky Object.
Save Land Object:The NexStar can also be used as a spotting scope on terrestrial objects. Fixed
land objects can be stored by saving their altitude and azimuth relative to the
location of the telescope at the time of observing. Since these objects are relative
to the location of the telescope, they are only valid for that exact location. To
save land objects, once again center the desired object in the eyepiece. Scroll
down to the "
Save Land Obj
" command and press ENTER. The display will
ask you to enter a number between 1-25 to identify the object. Press ENTER
again to save this object to the database.
Enter R.A. - Dec: You can also store a specific set of coordinates for an object just by entering the
R.A. and declination for that object. Scroll to the "
Enter RA-DEC
"
command and press ENTER. The display will then ask you to enter first the R.A.
and then the declination of the desired object.
GoTo Object: To go to any of the user defined objects stored in the database, scroll down to
either
GoTo Sky Obj
or
Goto Land Obj
and enter the number of the
object you wish to select and press ENTER. NexStar will automatically retrieve
and display the coordinates before slewing to the object.
To replace the contents of any of the user defined objects, simply save a new object using one of the existing
identification numbers; NexStar will replace the previous user defined object with the current one.
Get R.A./DEC. - Displays the right ascension and declination for the current position of the telescope.
Goto R.A./ DEC. - Allows you to input a specific R.A. and declination and slew to it.