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Autoguider calibration – Orion 52084 User Manual

Page 35

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autoguider Calibration

In order to properly control the mount, you must calibrate the system. The
exact orientation of the StarShoot Pro, the focal length of the guide telescope
optics, and the speed of the motor drive all affect the calibration. To perform
autoguider calibration:
1. Switch to the Guide tab.
2. Set the X and Y Aggr (aggressiveness) to 8 to start with. Set the Exposure

to 1.0 second. Under Guide Star, make sure the Watch box is checked.

Note: The X and Y Aggr (aggressiveness) controls on the Guide tab allows
you to adjust how vigorously star motions are tracked out in each axis. An
aggressiveness setting of 10 means that the StarShoot Pro attempts to track
out 100% of the motion, whereas a setting of 1 means that the StarShoot Pro
only tracks out 10% of the motion. Usually a setting of around 8 or 9 provides
the best tracking, since it reduces overshoot and helps ignore random motions
due to atmospheric seeing and wind loads. You should experiment to deter-
mine the best setting for your particular telescope.
3. Click the Settings button.
4. Maxim DL Essentials needs to know how fast the telescope moves in right

ascension (R.A.) and declination (Dec.) when the autoguider commands
are issued. To do this, the software will Calibrate the mount by moving it
back and forth on each axis. The Calibration Time determines how long it
activates the motors each time. The usual value is 5-10 seconds; start out
with a value of 5.

5. Make sure all of the Guider Enables boxes are checked.
6. For Autoguider Output, set Control Via and COM Port as required for

your telescope equipment. See “Computer to Mount Connection” if you
have not already done this.

7. Click Apply. You can leave this dialog box open, or Close it if you wish.
8. Make sure that the telescope mount is set to move at 1X sidereal or slower.

For some mounts, you must set the guide rate manually. The maximum
usable rate is 1X sidereal. If your mount does not drift quickly, then 0.1X is
recommended; otherwise use a value between 1X and 0.1X.

9. On the Guide tab, set to Expose, and click the Start button. A single

image will be taken. Ensure that a well-focused bright star (near the actual
object to be imaged) appears in the image. If not, adjust the guide scope
and try again. Make sure the star is roughly centered.

Note: The algorithm can be confused if another star appears in the frame; to
minimize this risk, calibrate on an isolated bright star.
10. Now, set to Calibrate, and click the Start button. A series of five expo-

sures will be taken; each time the telescope will be moved slightly. If the