15
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
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.
Button Direction Menu
