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Appendix A: ADVANCED ELECTRONIC CONTROLLER FUNCTIONS
Tracking Motor Speeds
In the polar mode the Electronic Controller normally tracks objects at the sidereal rate (see SIDEREAL RATE, page
13). For most observing sessions (once the telescope has been polar aligned and the tracking motor activated),
there is little need to change this speed.
For objects, like the Moon or a comet, that move at slightly different rates, the Electronic Controller Arrow keys (1, Fig.
3) are sufficient to move the telescope slightly as the object very slowly moves off-center through the eyepiece field.
To change the tracking rate, for extended observations of an object not moving at the sidereal rate, follow the
procedure for the appropriate hemisphere:
Northern Hemisphere Polar:
1. Press and hold the MODE key (5, Fig. 3) until the Mode function is active (i.e., lights 1 and 2 are on steady;
lights 3 and 4 signify whatever tracking mode was last chosen).
2. Press the SPEED key (3, Fig. 3) until lights 1, 2, and 3 are on steady with light 4 blinking. The telescope is
now in the Northern Hemisphere polar mode.
3. Press the IN key (7, Fig. 3) and light 4 comes on steady. The tracking rate is now 0.5% faster than sidereal.
If the object you're tracking is moving faster than the sidereal rate, look through the eyepiece and continue to
press the IN key until the object remains centered with little or no drifting in the eyepiece.
Note: The tracking rate can be increased by up to 65% (127 presses of the IN key).
4. To use a rate slower than sidereal, press the OUT (6, Fig. 3) key until light 4 blinks again (sidereal rate). Press
the OUT key again and light 4 goes out, signifying a tracking rate 0.5% slower than sidereal. If the object
you're tracking is moving slower than the sidereal rate, look through the eyepiece and continue to press the
OUT key until the object remains centered with little or no drifting in the eyepiece.
Note: The tracking rate can be decreased by up to 65% (127 presses of the OUT key).
5. Press and hold the MODE key until only a single light is on. This exits the Mode function. If Northern or
Southern Hemisphere polar mode was chosen, the motor drive starts operating at the sidereal rate.
6. Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,
press the SPEED key.
Southern Hemisphere Polar:
1. Press and hold the MODE key (5, Fig. 3) until the Mode function is active (i.e., lights 1 and 2 are on steady;
lights 3 and 4 signify the tracking mode last chosen).
2. Press the SPEED key (3, Fig. 3) until lights 1 and 2 are on steady, light 3 is off, and Light 4 is blinking.
3. Press the IN key (7, Fig. 3) and light 4 comes on steady. The tracking rate is now 0.5% faster than sidereal.
If the object you're tracking is moving faster than the sidereal rate, look through the eyepiece and continue to
press the IN key until the object remains centered with little or no drifting in the eyepiece.
Note: The tracking rate can be increased by up to 65% (127 presses of the IN key).
4. To use a rate slower than sidereal, press the OUT key (6, Fig. 3) until light 4 blinks again (sidereal rate). Press
the OUT key again and light 4 goes out, signifying a tracking rate 0.5% slower than sidereal. If the object
you're tracking is moving slower than the sidereal rate, look through the eyepiece and continue to press the
OUT key until the object remains centered with little or no drifting in the eyepiece.
Note: The tracking rate can be decreased by up to 65% (127 presses of the OUT key).
5. Press and hold the MODE key until only a single light is on. This exits the Mode function. If Northern or
Southern Hemisphere polar mode was chosen, the motor drive starts operating at the sidereal rate.
6. Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,
press the SPEED key.
Changing Modes Using the Electronic Controller
The Electronic Controller is in the Alt/Az mode when activated, unless a mode screw has been removed. To use
the Electronic Controller to change to Northern or Southern Hemisphere polar mode, or to use Alt/Az mode with
one of the mode screws removed, use the following procedure:
1. Complete the
POLAR ALIGNMENT PROCEDURE on page 16.
2. Complete steps 2 through 8 as described in TO MOVE THE TELESCOPE USING THE ELECTRONIC CONTROLLER,
page 15, to initialize the Electronic Controller.
3. Press and hold the MODE key (5, Fig. 3) until lights 1 and 2 are on steady and lights 3 and 4 start blinking.
4. Press the SPEED key (3, Fig. 3) once. This changes the system to polar mode for the Earth’s Southern
Hemisphere, with the motor drive set to operate at the sidereal rate.
5. Press the SPEED key a second time. This changes the system to polar mode for the Earth’s Northern
hemisphere, with the motor drive set to operate at the sidereal rate.
6. Press the SPEED key a third time and the system returns to the Alt/Az mode. In the Alt/Az mode the motor
drive does not activate when exiting from the Mode function.
7. Use the SPEED key as described in the above steps to cycle among these three modes (Alt/Az, Southern
Hemisphere polar, or Northern Hemisphere-polar) until the desired mode is shown by the appropriate light
configuration.
8. Press and hold the MODE key until just one light is on. This exits the Mode function. If you choose Northern
or Southern Hemisphere polar mode, the motor drive starts operating at the sidereal rate.
9. Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,
press the SPEED key.
Step 2.
Step 3.
Step 4.
Step 5.
Step 2.
Step 3.
Step 4.
Step 5.
Step 4.
Step 5.
Step 6.
Step 8.
Step 3.
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