Celestron NEXSTAR 8I, NEXSTAR 5I User Manual

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INTRODUCTION ...............................................................................................................................4

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......................................................................................................................................................4

QUICK SETUP ..................................................................................................................................6

Assembling the NexStar..................................................................................................................8

Powering the NexStar ..............................................................................................................................8

The Hand Control ....................................................................................................................................9

The Star Diagonal.................................................................................................................................... 9

The Eyepiece ............................................................................................................................................9

The Star Pointer Finderscope ................................................................................................................ 10

HAND CONTROL ............................................................................................................................12

Rate Button.............................................................................................................................................13

Utility Features ......................................................................................................................................14

OPTIONAL COMPUTERIZED HAND CONTROL ..........................................................................17

Hand Control Operation........................................................................................................................18

Alignment Procedures............................................................................................................................ 19

Auto-Align.......................................................................................................................................................... 19

Two-Star Alignment ...........................................................................................................................................20

Quick-Align........................................................................................................................................................21

GPS Alignment (with Optional CN 16 Accessory).............................................................................................21

EQ Alignments ...................................................................................................................................................22

Re-Alignment .....................................................................................................................................................23

Object Catalog ....................................................................................................................................... 23

Finding Planets......................................................................................................................................24

Tour Mode.............................................................................................................................................. 24

Direction Buttons ................................................................................................................................... 25

Rate Button.............................................................................................................................................25

Setup Procedures ...................................................................................................................................25

Tracking Mode....................................................................................................................................................25

Tracking Rate......................................................................................................................................................26

View Time-Site...................................................................................................................................................26

User Defined Objects..........................................................................................................................................26

Get RA/DEC....................................................................................................................................................... 27

Goto R.A/Dec .....................................................................................................................................................27

Scope Setup Features ............................................................................................................................. 27

Setup Time-Site ..................................................................................................................................................27

Anti-backlash......................................................................................................................................................27

Slew Limits.........................................................................................................................................................27

Filter Limits ........................................................................................................................................................27

Direction Buttons................................................................................................................................................27

Goto Approach....................................................................................................................................................28

Autoguide Rate...................................................................................................................................................28

Cordwrap ............................................................................................................................................................ 28

Utility Features ......................................................................................................................................28

GPS On/Off ........................................................................................................................................................28

Compass..............................................................................................................................................................28

Alt Sensor ...........................................................................................................................................................28

Wedge Align.......................................................................................................................................................29

Light Control ......................................................................................................................................................29

Factory Settings ..................................................................................................................................................29

Version................................................................................................................................................................29

Get Alt-Az .......................................................................................................................................................... 29

Goto Alt-Az ........................................................................................................................................................29

Hibernate ............................................................................................................................................................29

COMPUTERIZED HAND CONTROL QUICK SETUP ....................................................................31

TELESCOPE BASICS.....................................................................................................................33

Image Orientation .................................................................................................................................. 33

Focusing.................................................................................................................................................34

Calculating Magnification .....................................................................................................................34

Determining Field of View .....................................................................................................................34

General Observing Hints .......................................................................................................................35

ASTRONOMY BASICS ...................................................................................................................36

The Celestial Coordinate System ...........................................................................................................36

Motion of the Stars.................................................................................................................................37

Polar Alignment (with optional Wedge).................................................................................................38

Finding the North Celestial Pole ...........................................................................................................39

CELESTIAL OBSERVING ..............................................................................................................40

Observing the Moon............................................................................................................................... 40

Observing the Planets ............................................................................................................................ 40

Observing the Sun .................................................................................................................................. 40

Observing Deep Sky Objects..................................................................................................................41

Seeing Conditions ..................................................................................................................................41

Transparency .........................................................................................................................................41

Sky Illumination .....................................................................................................................................41

Seeing.....................................................................................................................................................41

CELESTIAL PHOTOGRAPHY........................................................................................................43

Short Exposure Prime Focus Photography............................................................................................ 43

Eyepiece Projection ...............................................................................................................................44

Long Exposure Prime Focus Photography............................................................................................45

Terrestrial Photography.........................................................................................................................47

CCD Imaging ......................................................................................................................................... 47

TELESCOPE MAINTENANCE........................................................................................................48

Care and Cleaning of the Optics............................................................................................................48

Collimation.............................................................................................................................................48

OPTIONAL ACCESSORIES ...........................................................................................................51

APPENDIX A – TECHNICAL SPECIFICATIONS ...........................................................................55

APPENDIX B – GLOSSARY OF TERMS .......................................................................................57

APPENDIX C –LONGITUDES AND LATITUDES ..........................................................................60

APPENDIX D – RS-232 CONNECTION (for Computerized Hand Control) ................................65

APPENDIX E – TIME ZONE MAPS ................................................................................................66

SKY MAPS ......................................................................................................................................68

Congratulations on your purchase of the Celestron NexStar! The NexStar i-series telescopes are precision scientific instruments that will allow you to enjoy viewing numerous objects in the night sky — planets, nebulae, star clusters, galaxies and more. Equipped with high speed motors and hand control, the NexStar-i allows you to remotely move your telescope to desired objects quickly and accurately. At a touch of a button, you can move your telescope across the sky in a matter of seconds and track objects remotely as the Earth rotates beneath them. The NexStar-i is fully upgradeable and can be equipped with the optional NexStar Hand Control with a database of over 40,000 objects (see the Computerized Hand Control section of this manual) for fully automated operation.

Some of the many standard features of the NexStar include:

• Incredible 6°/second (or faster) slew speed.

• Fully enclosed motors on both axes.

• Integrated hand controller – built into the side of the fork arm.

• Expandability to add smart accessories such as Computerized Hand Control and GPS capabilities.

Many other high performance features!

The NexStar’s deluxe features combine with Celestron’s legendary Schmidt-Cassegrain optical system to give amateur astronomers one of the most versatile and easy to use telescopes available on the market today.

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.

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Y 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.

Y 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.

Y 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.

Y 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

Figure 1-A - The NexStar i-Series

1 Optical Tube 6 Battery Compartment 2 Star Pointer Finderscope 7 ON/OFF Switch / 12v power

3 Eyepiece 8 Fork Arm

4 Star Diagonal 9 Electronic Hand Control

5 Focuser Knob 10 Schmidt Corrector Plate (not shown)

Remove the NexStar from its packaging and place the base on a sturdy, level surface. Remove the accessories from their individual boxes. Rotate the optical tube upwards so that you can access the battery compartment.

Battery Compartment

Remove the battery cover in the center of the base by gently lifting up on the round portion of the cover. Insert 8 AA batteries (user supplied) into the battery compartmen of the base. Replace the cover.

StarPointer

Findersco

) Attach the included accessories. Loosen the thumb screws on the side of the visual back and remove the protective plastic cap. Insert the star diagonal and eyepiece into the barrel of the visual back and tighten down all thumb screws. B) Remove the front lens cover from the end of the telescope. C) Attach the Star Pointer and turn it on by rotating the dial on the side. (For more information on attaching the accessories, see the Assembly section of manual).

Eyepiece

Star Diagonal

isual Back

On/Off Switch

Turn on the power to the NexStar by flipping the switch located at the bottom portion o the fork arm, to the "On" position.

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Direction Buttons

Use the arrow direction buttons to move the telescope and point it at a bright object such as the Moon. Press the RATE button to change the motor speed for fine centering.

Focus Knob

Rotate the focuser knob until the object in the eyepiece comes to a sharp, bright focus.

Look through the StarPointer finderscope and aim the telescope at a bright object until it is visible in the eyepiece. Use the hand control to place the object in the center of the

iece.

With the object centered in the eyepiece, use the azimuth and altitude adjustment knobs on the StarPointer to place the red alignment dot directly over the centered object.

Red

lignment

Dot

zimuth adjustment Knob

The NexStar comes completely pre-assembled and can be operational in a matter of minutes. The NexStar and its accessories are conveniently packaged in one reusable shipping carton that contains the following accessories:

• 25mm Plossl Eyepiece – 1¼"

• 1¼" Star Diagonal

• Star Pointer Finderscope and Mounting Bracket

• 1¼" Visual Back (attached to the optical tube)

• Electronic Hand Control

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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.

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The NexStar can be powered by eight user supplied AA batteries or with an optional AC adapter or cigarette lighter 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. Slowly rotate the optical tube upwards so that you have easy access to the battery compartment.

2. Remove the battery cover from the center of the base by gently lifting up on the round portion of the cover.

3. Insert the batteries into the battery compartment of the base.

4. Reattach the battery compartment door by gently pushing down on the cover until it snaps into place.

Battery Compartment

5. Turn on the power to the NexStar by flipping the

switch, located at the bottom portion of the fork arm, to the "On" position.

Figure 3-1: The NexStar can be powered

with 8 AA batteries.

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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 control into the cradle so that the opening in the back of the hand control slides over the clip inside the fork arm.

Once the telescope is powered up, use the hand control to move the optical tube to the horizontal position, this

NOTE

will make it more convenient to attach the necessary accessories as well as remove the front lens cover.

fork arm, lower the hand

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.

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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 visual back until its tip no longer extends into (i.e., obstructs) the inner diameter of the visual back.

2. Slide the chrome portion of the star diagonal into the visual back.

3. Tighten the thumbscrew on the visual back to hold the star diagonal in place.

If you wish to change the orientation of the star diagonal, loosen the thumbscrew on the visual back until the star diagonal rotates freely. Rotate the diagonal to the desired position and tighten the thumbscrew.

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The eyepiece, or ocular, is the optical element that magnifies the image focused by the telescope. The eyepiece fits into either the visual back directly or 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.

2. Slide the chrome portion of the 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 visual back. The NexStar uses eyepieces with a standard 1-1/4" barrel diameter.

StarPointe

Finderscope

Figure 3-2 - The Visual Accessories

Eyepiece

Star Diagonal

Visual Back

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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 two quick-release dovetail mounting brackets (one for the NexStar telescope and one for mounting the Star Pointer on other sized telescopes). Before the Star Pointer is ready to be used and properly aligned:

, it must be attached to the telescope tube

ariable Brightness

ON/OFF

Control

Glass Window

Altitude Control

Knob

Dovetail Mounting Bracket

Azimuth Control Knob

Mounting Track

Figure 3-3: The Star Pointer Finderscope with Mounting Bracket

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.

3. 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.

4. Without moving the main telescope, turn the Star Pointer's azimuth and altitude alignment controls until the red dot is directly over the alignment star.

If the LED dot is brighter than the alignment star, it may make it difficult to see the star. Turn the variable 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 . Remember to always turn

the power off after you have found an object. This will extend the life of both the battery and the LED.

The NexStar telescope is a precision scientific instrument that will allow you to enjoy viewing numerous objects in the night sky — planets, nebulae, star clusters, galaxies and more. Equipped with high speed motors and hand control, the NexStar allows you to remotely move your telescope to desired objects quickly and accurately. At a touch of a button, you can slew your telescope across the sky in a matter of second and track objects remotely as the Earth rotates beneath them. The NexStar is fully upgradeable and can be equipped with the optional NexStar Computerized Hand Control with a database of over 40,000 objects (see the computerized Hand Control section of this manual).

The NexStar has a removable hand control that gives the user quick access to all the motion controls the NexStar has to offer. Below is a brief description of the individual components of the NexStar hand controller:

1. Star Key Activation Light: Indicates that the Star button has been pressed and the utility functions on the hand control are active.

2. Direction Buttons: Allows complete control of the NexStar in any direction. Use the direction keys to move the telescope from object to object or for centering objects in the eyepiece.

3. Rate: Instantly changes the rate of speed of the motors when the direction buttons are pressed. Press this button repeatedly to cycle through the speeds of the motors.

4. Star Key: Gives the user access to the utility functions of the hand control, such as changing the direction of the arrow keys and backlash compensation.

5. Slew Rate/Menu Indicator Lights: Displays the speed at which the telescope will move when each direction button is pressed. Also indicates which utility mode you are when the Star Key Activation Light (1) is on.

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Figure 4-1

The NexStar Electronic Hand Control

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Pressing the RATE key (3) allows you to instantly change the speed rate of the motors from high speed slew rate to precise centering rate and four speeds in between. Each rate corresponds to one of the indicator LED lights (5) on the hand control. From left to right, the corresponding speeds are as follows:

Rate Speed Double Button Speed

1 For fine centering of objects in the eyepiece 8x Sidereal* 16x Sidereal*

2 For scanning around for objects in the eyepiece 64x Sidereal 128x Sidereal

3 For centering bright stars in the StarPointer

4 For slewing around the sky from object to object 6º per second N/A

*When used in the equatorial tracking modes, track rate 1 is equal to 1.5x sidereal, and 2x when using the double button.

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 slew rate to the next highest available rate.

Note: When your NexStar is first powered on, the slew speed automatically defaults to rate 4 (6º per second). This allows you to be able to move the telescope at its fastest rate as soon as it is turned on.

2º per second 6º per second

Finderscope

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The NexStar electronic hand control comes with a Star function key that allows you to change certain parameters of the hand controls functions, such as the tracking mode, the directional logic of the arrow keys and backlash compensation of the motor gears and azimuth tracking.

Tracking Mode: The NexStar electronic hand control allows your telescope to track objects in the following modes: EQ North, EQ South, Alt-Az and Terrestrial (off). By default the tracking motors are turned off, allowing you to slew the telescope and observe land objects. If using your NexStar on an optional equatorial wedge, it will be necessary to turn the tracking motor on. To turn on the tracking motors:

• Press the STAR key on the hand control. The star light (1) on the hand control will light up to indicate that the button has been pressed and the first (left most) indicator light will be lit showing that you are in the tracking menu with tracking set to off. (see figure).

• Press the RATE button once to select equatorial tracking in the Northern Hemisphere.

• Press the RATE button twice to select equatorial tracking in the Southern Hemisphere.

• Press the RATE button three times to select Alt-Az tracking.

Once set continue pressing the STAR button until the star light goes off.

Alt-Az Tracking – The NexStar gives you the ability to adjust the tracking speed in both altitude (up and down) and azimuth (side to side) to allow you to track an object as it moves across the sky. Once a celestial object is centered in the field of view of the eyepiece, notice which direction the object appears to drift in the eyepiece. Using the arrow buttons, determine which buttons you need to press in order to move the object back to center. Which ever buttons that you use to center the object will be the same buttons you will need to adjust when setting the Alt-Az motor speed. The direction and speed at which an object drifts out of the field of view of the eyepiece depends on what part of the sky the object is located. This mean that Alt-Az tracking will need to be adjusted each time you move the telescope significantly to a different part of the sky. For guidelines and tips on correctly adjusting your Alt-Az tracking speed, see the table at the end of this section. To set the Alt-Az tracking rate, do the following:

1. Once the desired object is centered in the eyepiece and you have determined which arrow buttons need to be pressed to keep the object centered, press the STAR key on the hand control.

2. Press the RATE button three times to select Alt-Az tracking.

3. Select the arrow button that you were using to center the object and press it once. This will increase the motor speed in that direction. If the star continues to drift in the same direction as before, press the same direction button until the star no longer drifts in that direction. If the star begins to drift in the opposite direction, then press the opposite arrow button to reverse the motion. Use the table at the end of this section to help determine the initial tracking rates.

4. Using the remaining two arrow buttons, repeat the same process for the telescope’s other axis if necessary.

Note: You can adjust both axes at the same time if you wish. A reticle or crosshair eyepiece can be helpful in detecting subtle drift and determining direction of movement.

Anti-backlash – All mechanical gears have a certain amount of backlash or "play" between the gears. This play is evident by how long it takes for a star to move in the eyepiece when the hand control direction buttons are pressed (especially when changing directions). The NexStar's anti-backlash feature allows the user to compensate for backlash by having the hand control quickly rewinding the motors enough to help reduce the play between the gears. The amount of compensation needed depends on the slewing rate selected; the slower the slewing rate the longer it will take for the star to appear to move in the eyepiece. The NexStar hand control allows you to change the backlash setting for each axis, one at a time. To change the backlash compensation:

1. Press the STAR key on the hand control. The activation light (1) on the hand control will light up to indicate that you have activated the menu functions.

Backlash Compensation Menu

2. Press the STAR button on the hand control again or until the second indicator light from the left is on (see figure).

3. Select the direction you which to set and press the corresponding arrow keys to increase the initial speed of the motors when that arrow button is pressed (once a button is pressed, all the indicator lights except the second from the left will illuminate). For example, if it takes a star too long to move in the eyepiece when the right hand control arrow button is pressed, then press the Right arrow button to speed up the initial motor speed. The buttons can be pressed repeatedly to increase the initial motor speed even more. Pressing the opposite button will decrease the initial motor speed.

4. To decrease the initial speed of the motor, you must first press the direction button that corresponds to the direction you wish to adjust, then press the opposite direction button to decrease the rate.

5. Press the RATE button to save the new backlash values and return to the backlash menu.

6. If necessary, repeat steps 3 and 4 by selecting the remaining directions and pressing the corresponding arrow keys to set the backlash value to the desired level.

7. Once complete, Press the RATE button to save the new backlash values.

Adjusting the backlash values is an iterative process and may require you to repeat these steps until the desired button response is achieved. Once saved, backlash values will be retained for future use until they are changed.

Direction Buttons: When looking at a star through an eyepiece or star diagonal, the direction that the star moves when the Up and Down arrow buttons are pressed will be reversed from when the same object is being centered in the Star Pointer Finderscope. For example, when a star is being centered in the telescope's eyepiece, it may appear to move upward when the down arrow button is pressed (and visa-versa) even though the telescope tube is actually moving downward. This is why it is convenient to be able to change the direction of the arrow buttons. To reverse the direction of the Up and Down arrow buttons:

1. Press the STAR key on the hand control. The activation light (1) on the hand control will light up to indicate that the button has been pressed.

2. Press the STAR button on the hand control two more times or until the third indicator light from the left is on (see figure).

3. Pressing any one of the four direction buttons will change the direction of the corresponding button when used in rates 1 and 2 (eyepiece rates). The movement for rates 3 and 4 (slew rates) will always remain unchanged. To change the button direction back to where it was, you can either press the same direction button again or press the opposite direction button. All four indicator lights will light up to acknowledge the button was pressed. The lights will go back to their previous state when the direction button is released.

How to Set Alt-Az Tracking

Button Direction Menu

In order for an Alt-Az telescope to accurately track objects in the sky, it must be able to speed up and slow down the altitude and azimuth motors in order to keep up with the way the stars naturally travel in an arc across the sky. A fully computerized telescope, such as your NexStar-i used with the optional computerized hand control (#93962), automatically knows what part of the sky it is pointed and can therefore increase or decrease the speed of the motors as necessary to track objects. Your NexStar telescope with its standard electronic hand control allows you to manually change the tracking motor speed to more accurately follow celestial objects in different locations in the sky. When using the Alt-Az tracking feature keep in mind that as you track a star that is higher in altitude, the azimuth speed increases the closer you are to the meridian (in this case, due south). The altitude motor speed, on the other hand, will need to be decreased as you get closer to the meridian. Objects in the northern portion of the sky will move much slower, but the direction of drift will change depending on which side of Polaris (the North Star) the object is located.

To help you determine how much you will need to speed up or slow down the tracking motors, the following tables provides information on the proper settings for your hand control when pointing at objects in different parts of the sky. The tables show the required tracking rate and corresponding hand control setting for objects of different altitudes located in different portions of the sky. The table assumes the observer is at a latitude of 40°, however the data is relatively accurate from latitudes 30° to 50°. To help illustrate how to use the table, take an example of a star that is located in the south-east at an altitude of 25°. While looking at that star in the eyepiece you will notice that it drifting out of the eyepiece in a particular direction. Once in Alt-Az tracking mode, press the direction buttons that correspond to the opposite direction of the star’s drift the amount of times shown in the table. For our example, you would need to press the corresponding azimuth button 3 times and the altitude button 2 times. Of course these setting are only approximate depending on the exact location of the star in the sky. You can then make minor adjustments as you notice further star drift.

Altitude 25°, Latitude 40°

South East / South West South North East / North West

Track Rate

Azimuth .87x sidereal

Altitude ±.53x sidereal

Number of button presses* 3

Track Rate

1x sidereal

0x sidereal

Number of button presses 4

Track Rate

.4x sidereal

±.53x sidereal

Number of button presses 2

*Each button press increases the motor speed by .25 times sidereal

Altitude 55°, Latitude 40°

South East / South West South North East / North West

Track Rate

Azimuth 1.4x sidereal

Altitude ±.53x sidereal

Number of button presses 6

Track Rate

1.7x sidereal

0x sidereal

Number of button presses 7

Track Rate

-.13x sidereal

±.53x sidereal

Number of button presses 1

Altitude 70°, Latitude 40°

South East / South West South North East / North West

Track Rate

Azimuth 2.1x sidereal

Altitude ±.53x sidereal

Number of button presses 9

Track Rate

2.7x sidereal

0x sidereal

Number of button presses 11

Track Rate

-.8x sidereal

±.53x sidereal

Number of button presses 3

Alt-Az

Tracking

When pressing the hand control buttons to set the Alt-Az track rate, use the “double button” feature to increase the rate in larger steps. Each time you use the double button the track rate will increase by 1x sidereal. For Example, if you wish to track a star in the south that is at 70° altitude (see table for Altitude 70°), instead of pressing the azimuth button 11 times you could use the double button twice and then press the single button 3 times.

Your NexStar i-Series telescope is compatible with many NexStar accessories including the Computerized Hand Control. The NexStar Computerized Hand Control gives you instant access to all the functions 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 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 move the telescope to the initial alignment stars or for centering objects in the eyepiece.

The NexStar Computerized Hand Control

Figure 5-1

4. Catalog Keys: The NexStar has keys on the hand control to allow direct access to each of the catalogs in its database. The NexStar 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 NexStar

database have been broken down into customized lists based on their type and/or common name:

Named Stars

Named Objects

Double Stars

Variable Stars

Asterisms

CCD Objects

IC Objects

Abell Objects

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 the current date and time, and automatically slews the NexStar to those objects.

7. Enter: Pressing Enter allows you to select any of the NexStar 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 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 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 NexStar remotely.

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Common name listing of the brightest stars in the sky. Alphabetical listing of over 50 of the most popular deep sky objects. Numeric-alphabetical listing of the most visually stunning double, triple and quadruple stars in the sky. Select list of the brightest variable stars with the shortest period of changing magnitude. A unique list of some of the most recognizable star patterns in the sky. A custom list of many interesting galaxy pairs, trios and clusters that are well suited for CCD imaging. A complete list of all the Index Catalog deep-sky objects. A complete list of all the Abell Catalog deep-sky objects.

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 utilities functions such as the slew limits, database filter limits and backlash compensation.

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In order for the NexStar to accurately point to objects in the sky, it must first be aligned to two 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: AutoAlign will ask the user to input date and location information in order to locate the alignment stars; Two-Star Alignment does not require the user to input date and location data, but does require the user to identify and manually slew the telescope to the two alignment stars. Quick-Align will ask you to input all the same information as you would for the AutoAlign procedure. However, instead of slewing to two alignment stars for centering and alignment, the telescope bypasses this step and simply models the sky based on the information given. And used in conjunction with the optional CN16 GPS accessory, GPS Align Mode allows the NexStar to acquire all the necessary information needed to point itself to the required alignment stars. Finally, EQ North and EQ South alignments are designed to assist you in aligning the NexStar when polar aligned using an equatorial wedge. Each alignment method is discussed in detail below.

Auto-Align

AutoAlign allows the user to input all the necessary information needed to align the telescope. After choosing AutoAlign, the NexStar will ask you to input first the date and local time information then it will ask for your location. Once this information is received, NexStar will prompt you to move the telescope in altitude to line up the two index marks on the fork arm. The final step is to rotate the telescope so that the tube is pointing towards the north. The NexStar now has all the information it needs to choose two bright alignment stars and automatically slew to them.

With the NexStar set up outside with all accessories attached, follow the steps below to AutoAlign the NexStar:

1. Once the NexStar is powered on , Press ENTER to begin alignment.

2. Use the Up and Down scroll keys (10) to select AutoAlign and press ENTER.

3. The hand control will then display the following information for you to accept or modify. Use the Up and Down scroll buttons (10) to scroll through the information. If any of the parameters need to be updated, press the UNDO button and enter the current information. If all the information is correct, press ENTER to accept .

(Note: the NexStar will always retain the most recent time/site information entered into the hand control unless the optional CN16 GPS accessory is being used. When using the CN16, the GPS receiver will update local time and location information automatically)

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 E for more information.

Date - Enter the month, day and year of your observing session.

If 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.

4. Finally, you must enter the longitude and latitude of the location of your observing site. Use the table in Appendix C to locate the closest longitude and latitude for your current observing location and enter those numbers when asked in the hand control, pressing ENTER after each entry. Remember to select "West" for longitudes in North America and "North" for latitudes in the North Hemisphere. For international cities, the correct hemisphere is indicated in the Appendix listings.

5. The hand control will then prompt you to move the optical tube to its north and index position:

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• Use the up and down arrow keys (3) keys to rotate the telescope tube until the index marker that

moves with the optical tube is lined up with the stationary index marker on the fork arm. See figure 5-2.

• Use the left and right arrow keys to point the front of the telescope towards north. North can be

found by finding the direction of the North Star (Polaris) or by using a compass. You do not need to point at the North Star, only the north horizon. Alignment only needs to be approximate, however a close alignment will make the auto alignment more accurate. Once the telescope is in the north and index position, press ENTER.

Based on this information, the NexStar will automatically select a bright star that is above the horizon and slew towards it. At this point the telescope is only roughly aligned, so the alignment star should only be close to the field of view of the Star Pointer finderscope. Once finished slewing, the display will ask you to use the arrow buttons to align the selected star with the red dot in the center of the Star Pointer. If for some reason the chosen star is not visible (perhaps behind a tree or building) you can press UNDO to select and slew to a different star. Once centered in the Star Pointer, 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 first alignment star. After the first alignment star has been entered the NexStar will automatically slew to a second alignment star and have you repeat this procedure for the second star. When the telescope has been aligned to both stars the display will read Alignment Successful, and you are now ready to find your first object.

If the wrong star was centered and aligned to, the NexStar display will read Alignment Failed and scroll the message, "the positions of the alignment stars did not match the database". Should this occur, press the UNDO button and re-align the telescope. Remember the alignment star will always be the brightest star nearest the field of view of the finderscope.

For the best possible pointing accuracy, always center the alignment stars using the up arrow button and the right arrow button. 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. However, if the “Goto Approach” of the telescope has been changed (see ”Goto Approach” later in this section), then remember to always center the alignment stars in the same direction that the telescope centers objects when completing a slew.

Figure 5-2 –The Altitude Index Markers for the

NexStar 5i (left) and the NexStar 8i (right).

Two Star Alignment

With the two-star alignment method, the NexStar requires the user to know the positions of only two bright stars in order to accurately align the telescope with the sky and begin finding objects. Here is an overview of the twostar 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. The NexStar display the message Set Alt to Index . Use the Up and Down direction keys (3) and rotate the telescope tube until the index marker that moves with the optical tube is lined up with the stationary index marker on the fork arm (See figure 5-2). Press ENTER.

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.

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4. NexStar then asks you to center in the eyepiece the alignment star you selected. Use the direction buttons to slew the telescope to the alignment star and carefully center the star in the eyepiece.

In order to accurately center the alignment star in the eyepiece, it will be necessary 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).

5. Once the alignment star is centered in the field of view of the eyepiece, press the ALIGN key (2) to accept this position.

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 Alignment Successful, and you will hear the tracking motors turn-on and begin to track.

Quick-Align

Quick-Align allows you to input all the same information as you would for the AutoAlign procedure. However, instead of slewing to two alignment stars for centering and alignment, the NexStar 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 NexStar the information needed to track objects in altazimuth in any part of the sky. 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:

1. Select Quick-Align from the alignment options.

2. Use the direction buttons to move the telescope to its north and index position and press ENTER.

3. The hand control will then ask you to input all the same time and location information as you would for the AutoAlign procedure.

4. Once in position, the NexStar will model the sky based on this information and display Alignment Successful.

Note: Once a Quick-Align has been done, you can use the Re-alignment feature (see below) to improve your telescopes pointing accuracy.

GPS Alignment (with Optional CN 16 Accessory)

The following section describing a GPS assisted alignment applies only if using the CN16 GPS accessory (#93963) in conjunction with your NexStar i-Series telescope. If you are not using a CN16 GPS with your telescope, skip this section and follow the alignment steps described in the AutoAlign section. For more information about the CN16 GPS accessory, please see the Optional Accessories section of this manual.

GPS Align must be used with the telescope mounted in altazimuth. With GPS Align mode, the NexStar automatically levels the optical tube, its built-in electronic compass points the telescope in the direction of the northern horizon, while the GPS receiver links with and acquires information from 3 of the orbiting GPS satellites. With this information, the built-in GPS system calculates the scope’s location on Earth with an accuracy of a few meters and calculates universal time down to the second. After quickly making all these calculations and automatically entering the information for you, the NexStar GPS orients itself with the sky, slews to an alignment star and asks you to position the star in the center of the eyepiece. The NexStar is then ready to start finding and tracking any of the objects in its 40,000+ 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. Before turning on the NexStar, make sure that the tube is pointed downward and both the altitude and azimuth clutches are locked down. To begin the GPS alignment:

Definition

ltazimuth - 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 without the use of an equatorial wedge.

1. Power on the NexStar by flipping the switch located on the bottom portion of the drive base, to the "on" position. Once turned on the hand control display will say NexStar Ready. Press ENTER to choose GPS Align or use the UP/Down scroll keys (10) to select a different mode of alignment. Pressing the ALIGN key will bypass the other alignment options and the scrolling text and automatically begins GPS

Align.

2. Once GPS Align has been selected, the telescope will use its internal compass to move towards north and find its altitude switch. While the NexStar is positioning itself, the GPS receiver automatically begins to establish a link with the GPS satellites orbiting the Earth. The hand control screen will display the message GPS Linking to let you know that it is linking with the satellites.

3. Once the NexStar has established a link with the required satellites, the hand control display will read GPS Linked. The GPS satellites will then report the current time and position directly to your NexStar. The NexStar now has all the necessary data to make a virtual model of the sky, select two bright stars for alignment and begin slewing to the first star.

4. When the NexStar has finished slewing to its first alignment star, the hand control display will ask you to use the arrow buttons to center the alignment star in the cross hairs of the finderscope. At this point the telescope is only roughly aligned, so the alignment star should only be close to the field of view of the finderscope. Once centered in the finderscope, press ENTER. If for some reason the chosen star is not visible (perhaps behind a tree or building) you can press the UNDO button to have the NexStar select and slew to a different star.

5. 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 NexStar 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).

After the first alignment star has been recorded, the NexStar will automatically slew to a second alignment star and have you repeat the alignment process for that star. When the telescope has been aligned to both stars, the display will read "Alignment Successful" and you are now ready to find your first object.

EQ North / EQ South Alignment

EQ North and EQ South Alignments assist the user in aligning the telescope when polar aligned on an optional equatorial wedge. Just as with the Altazimuth alignments described earlier, the EQ alignments gives you the choice of performing an AutoAlign or a Two-Star alignment.

• The EQ AutoAlign follows many of the same steps as the Alt-Az AutoAlign, except instead of asking you to position the scope towards north, it will ask you to position the tube so that the index markers are aligned, and then rotate the telescope base until the tube is pointed towards the Meridian (see figure 5-3).

• The EQ Two-Star Align requires the user to locate and align the telescope on two bright stars. When selecting alignment stars it is best to choose stars that, a) have a large separation in azimuth and b) both are either positive or negative in declination. Following these two guidelines will result in a more accurate EQ Two-Star alignment.

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 directl

overhead to the North celestial pole.

Figure 5-3

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NexStar Re-Alignment

The NexStar has a re-alignment feature which allows you to replace either of the two original alignment stars with a new star or celestial object. This can be useful in several situations:

• If 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.

• If you have aligned your telescope using the Quick-Align method, you can use re-align to align to two actual objects in the sky. This will improve the pointing accuracy of your telescope without having to reenter 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 Ready displayed, press the ALIGN key on the hand control.

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. It is usually best to replace the star closest to the new object. This will space out your alignment stars across the sky.

6. Press ALIGN to make the change.

Since many planets and bright stars can be observed in the daytime, the realign feature can also be useful for aligning your telescope during the day. Daytime alignments require the use of a proper solar filter for your telescope (see Optional Accessories section of the manual). In order to align the NexStar in the daytime, you will need to perform a Quick Align as discussed earlier in this section and then use the Sun as your alignment star. Follow these steps to align your NexStar in the daytime:

1. Perform a Quick Align as discussed earlier in this chapter.

2. With the proper solar filter attached, manually move the telescope to the Sun and center it in the eyepiece.

3. Once centered, press the UNDO button until you are at the main menu.

4. With NexStar Ready displayed, press the ALIGN key on the hand control

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. Since you did a Quick-Align it does not matter which star you select.

6. Press the ZERO button on the hand control.

7. The hand control will then prompt you to "Center the Sun" and "Press Align"

8. For your second star alignment, do one of the following

• Select a bright star or planet from the database and slew to it. If it is visible in the eyepiece, use that object to realign to, replacing the remaining star when asked to choose.

• Wait approximately 10 minutes, and go through steps 2-7 above and again use the Sun as the second alignment object. Replace the remaining star when asked to choose.

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Selecting an Object

Now that the telescope is properly aligned, you can choose an object from any of the catalogs in the NexStar's extensive database. The hand control has a key (4) 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.

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, Asterisms and CCD Objects. Selecting any one of these catalogs will display a numeric-

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Celestron NEXSTAR 8I, NEXSTAR 5I User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual