Celestron NexStar HC 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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INTRODUCTION ........................................................................................................................................ 4
WARNING.................................................................................................................................................... 4
QUICK SETUP ............................................................................................................................................. 5
ASSEMBLY .................................................................................................................................................. 8
ASSEMBLING THE NEXSTAR........................................................................................................................ 8
Powering the NexStar ............................................................................................................................ 8
The Hand Control .................................................................................................................................. 9
The Eyepiece .......................................................................................................................................... 9
The Star Pointer Finderscope .............................................................................................................. 10
NEXSTAR HC MODEL ........................................................................................................................... 12
THE HAND CONTROL ................................................................................................................................12
Rate Button........................................................................................................................................... 13
Utility Features .................................................................................................................................... 13
GuideStar Software .............................................................................................................................. 14
NEXSTAR GT MODEL............................................................................................................................. 15
HAND CONTROL OPERATION .................................................................................................................... 16
Alignment Procedure ........................................................................................................................... 16
OBJECT CATALOG ..................................................................................................................................... 18
Selecting an Object .............................................................................................................................. 18
Slewing to an Object ............................................................................................................................ 18
Tour Mode............................................................................................................................................ 19
DIRECTION BUTTONS ................................................................................................................................19
Rate Button........................................................................................................................................... 19
SETUP PROCEDURES.................................................................................................................................. 20
Tracking Mode ..................................................................................................................................... 20
Tracking Rate....................................................................................................................................... 20
Date/Time............................................................................................................................................. 21
User Defined Objects ........................................................................................................................... 21
Get RA/DEC......................................................................................................................................... 21
Get Alt-Az............................................................................................................................................. 21
Goto R.A/Dec ....................................................................................................................................... 21
Goto Alt-Az........................................................................................................................................... 22
UTILITY FEATURES ................................................................................................................................... 22
Cord Wrap.......................................................................................................................................... 22
Anti-backlash ..................................................................................................................................... 22
Model Select....................................................................................................................................... 22
Hand Control Command Tree.............................................................................................................. 23
TELESCOPE BASICS ............................................................................................................................... 24
IMAGE ORIENTATION ................................................................................................................................24
FOCUSING ................................................................................................................................................. 25
CALCULATING MAGNIFICATION................................................................................................................ 25
DETERMINING FIELD OF VIEW .................................................................................................................. 25
GENERAL OBSERVING HINTS .................................................................................................................... 26
ASTRONOMY BASICS................................................................................................................................. 27
THE CELESTIAL COORDINATE SYSTEM ..................................................................................................... 27
MOTION OF THE STARS ............................................................................................................................. 28

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POLAR ALIGNMENT (WITH OPTIONAL WEDGE) ......................................................................................... 29
Photography with the NexStar 4 .......................................................................................................... 30
Finding the North Celestial Pole ......................................................................................................... 31
CELESTIAL OBSERVING....................................................................................................................... 32
OBSERVING THE MOON ............................................................................................................................. 32
OBSERVING THE PLANETS ......................................................................................................................... 32
OBSERVING THE SUN................................................................................................................................. 33
OBSERVING DEEP SKY OBJECTS ............................................................................................................... 33
SEEING CONDITIONS ................................................................................................................................. 33
Transparency ....................................................................................................................................... 33
Sky Illumination ................................................................................................................................... 33
Seeing................................................................................................................................................... 34
TELESCOPE MAINTENANCE ............................................................................................................... 35
CARE AND CLEANING OF THE OPTICS ....................................................................................................... 35
OPTIONAL ACCESSORIES .................................................................................................................. 36
APPENDIX A - TECHNICAL SPECIFICATIONS................................................................................ 39
APPENDIX B - GLOSSARY OF TERMS ............................................................................................... 40
APPENDIX C – MAPS OF TIME ZONES .............................................................................................. 43
SKY MAPS.................................................................................................................................................. 45

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Congratulations on your purchase of the Celestron NexStar! 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 two alignment stars.
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 an experienced amateur, you will appreciate the comprehensive database of
over 4,000 objects, including customized lists of all the best deep-sky objects, bright double stars and variable 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:
• Incredible 4°/second slew speed.
• Fully enclosed motors and optical encoders for position location.
• Integrated hand controller – built into the side of the fork arm.
• Storage for programmable user defined objects; and
Many other high performance features!
The NexStar’s deluxe features combine with Celestron’s legendary optics to 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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Attach the included accessories (eyepiece and Star
Pointer finderscope) and remove the front lens
cover. Turn-on the Star Pointer by rotating the dial
on the side. (For instructions on aligning the Star
Pointer see the Assembly section of the manual).
Rotate the tube so it is level with the ground. Lift
the battery compartment cover to install batteries.
Power the NexStar using the switch next to the 12v
outlet at the base of the fork arm.
Remove the NexStar from its packaging and place
the base on a sturdy, level surface. Remove the
accessories from their individual boxes.
Once powered on, the display will read NexStar Ready.
Press ENTER to AutoAlign the NexStar. The hand control
display will ask you to move the telescope tube so that it is
level with the ground and facing the north horizon. Use
the UP and Down arrow buttons to position the telescope
North and level. (See Astronomy Basics for help on finding
North). The first time the NexStar is powered-on, you may
be prompted to select your telescope model. If so, see the
section on hand control operation for instruction.
4
Focuser Knob
StarPointerEyepiece
Flip Mirror
Battery Compartment
Cover

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Input the necessary date and time information as
instructed by the hand control. Press ENTER after
each entry. The NexStar will also ask for time zone
and location information. Use the UP and Down scroll
buttons to select from the various options, pressing
ENTER after each selection. (See Hand Control
section for detailed ali
g
nment
p
rocedures
)
.
Up and Down
Scroll Buttons
Direction
Buttons
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The NexStar will automatically pick an alignment star and slew
the telescope close to that star. Once there, the display will as
k
you to use the arrow buttons to aim the Star Pointer at the star. I
f
the star is not visible (perhaps behind a tree), press UNDO to
select a new star. Next, center the star in the eyepiece and press
ALIGN. Repeat these steps for the second star alignment. When
complete, display will read "Alignment Successful"
Alignment Successful"Alignment Successful"
Alignment Successful".
Press the TOUR button on the hand control. The hand control
will display a list of objects that are visible for the date and
location entered. Press INFO to read information about the
object displayed. Press the DOWN scroll key to display the
next object. Press ENTER to slew to (go to) the displayed
object.
TOUR Button
Object List
Button
Catalog Keys
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Alignment Star
Star Pointer Finderscope
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1 Optical Tube 6 Focuser Knob
2 Liquid Crystal Display 7 Straight Through Photographic Adapter
3 Hand Control 8 Flip Mirror Control
4 ON/OFF Switch 9 Eyepiece
5 Battery Compartment 10 Star Pointer Finderscope
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The NexStar 4 comes completely pre-assembled and can be operational in a matter of minutes. The NexStar is conveniently
packaged in one reusable shipping carton that contains all of the following accessories:
• 25mm SMA Eyepiece – 1¼"
• Star Pointer Finderscope and Mounting Bracket
• The Sky® for Celestron Astronomy Software
A
As ss se em mb bl li in ng g t th he e N Ne ex xS St ta ar r
Start by removing the telescope from its shipping carton and setting the round base on a flat table or surface. It is best to
carry the telescope by holding it from the lower portion of the fork arm and from the bottom of the base. 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 the batteries can be installed, the telescope tube should be positioned horizontal to the ground. To do this,
gently rotate the front of the tube upwards until it is level with the ground.
Powering the NexStar
The NexStar can be powered by eight AA batteries (not included), an optional 12v AC adapter or an optional car battery
adapter. The battery compartment is located in the center of the telescope's base (see figure 3-1).
To power the NexStar with batteries:
1. Remove the battery cover from the center of the base by
gently lifting up on the round portion of the cover.
2. Insert the batteries into the battery compartment of the base.
3. Reattach the battery compartment door by gently pushing
down on the cover until it snaps into place.
4. Turn on the power to the NexStar by flipping the switch,
located at the base of the fork arm, to the "On" position.
Battery Compartment
Cover
Figure 3-1: The NexStar 4 Battery Compartment

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The Hand Control
The hand control is located on the side of the fork arm and can be removed and used remotely or used while attached to the
fork. The hand control attaches to the fork arm by resting on two posts, located on the bottom of the hand control cradle,
and a clip inside the fork arm. To remove the hand control from the fork arm cradle, gently lift the hand control upwards
and pull out. To return the hand control into the fork arm, lower the hand control into the cradle so that the two holes in the
bottom of the hand control go over the posts on the bottom of the cradle, and the opening in the back of the hand control
slides over the clip inside the fork arm.
Once the telescope is powered up, the hand control can be used to move the optical tube in altitude (up and down) and
azimuth (side to side).
• Press UNDO (for GT model only). This will bypass the normal alignment procedures and will still allow you to control
the telescope.
• Use the Up arrow directional button to move the telescope tube until it is roughly parallel to the ground. This will
make it more convenient to attach the necessary accessories as well as remove the front lens cover and install batteries
when they are needed.
You are now ready to attach the included visual accessories onto the telescope optical tube.
The Eyepiece
The eyepiece, or ocular, is the optical element that magnifies the
image focused by the telescope. The NexStar 4 has an internal
diagonal mirror that diverts light to the eyepiece barrel on top of
the telescope's rear cell. The eyepiece fits into the barrel built-in
to the rear cell. To install the eyepiece:
1. Loosen the thumbscrew on the eyepiece barrel so it does not
obstruct the inner diameter of the barrel.
2. Slide the chrome portion of the eyepiece into the eyepiece barrel.
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 telescope's eyepiece barrel. The NexStar uses eyepieces with
a standard 1-1/4" barrel diameter.
As mentioned, the NexStar has an internal flip mirror that can divert light either through the eyepiece barrel at the top of the
rear cell or directly through the photographic opening at the back of the rear cell. Make sure that the flip mirror is in the
"up" position for viewing with an eyepiece and in the "down" position for taking photographs (see Astronomy Basics section
of the manual).
Figure 3-2 – The Rear Cell with Visual Accessories
Focuser Knob
StarPointerEyepiece
Flip Mirror Control
Diagonal
Barrel
Note:

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The Star Pointer Finderscope
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 a quick-release dovetail mounting bracket. Before the Star Pointer is ready to be used, it must be
attached to the telescope tube and properly aligned:
Star Pointer Installation
1. First, remove the two 8-32 x ¼" screws located on the top portion of the telescope's rear cell.
2. Locate the square dovetail bracket that has the proper curvature for the NexStar tube and align the holes with the two
holes in the telescope body.
3. Use the two 8-32 x ¼" screws to tighten down the bracket to the rear cell.
4. Once the bracket is mounted, slide the mounting track at the bottom of the Star Pointer over the dovetail portion of the
bracket. It may be necessary to loosen the two screws on the side of the mounting track before sliding it over the
dovetail. The end of the Star Pointer with the glass window should be facing out towards the front of the telescope.
5. Tighten the two screws on the side of the mounting track to secure the Star Pointer to the dovetail bracket.
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. To turn on the Star Pointer, rotate the variable brightness control (see figure 3-3) 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.
2. Locate a bright star or planet and center it in a low power eyepiece in the main telescope.
Azimuth Control
Knob
Dovetail Mounting Bracket
Mounting Track
ON/OFF
Variable Brightness
Control
Altitude Control
Knob
Figure 3-3: The Star Pointer Finderscope with Mounting Bracket
Glass Window