AUTOSTAR INFORMATION Last updated: 30 November 2000

Autostar Drive Training Adjustment

PROBLEM SYMPTOMS:

Some ETX/Autostar users see a condition in which attempting to move an object to the left in the FOV with the left arrow key results in the 'scope undoing the movement some ten or fifteen seconds later; in some cases the problem is so extreme that the final location of the object is further to the right than before the movement was attempted. The problem is practically nil near Polaris and becomes more pronounced as the telescope is aimed toward the celestial equator.

This condition appears to be related to azimuth backlash compensation routines in the Autostar and it is possible that it might be fixed by applying the "creep after beep" patch found here. I have not had a chance to load the patched binary and evaluate.

However, I have found that feeding a bit of incorrect information to the azimuth training routine will greatly reduce the problem.

WORK-AROUND PROCEDURE:

1. Set up for azimuth training by placing your target object in the far left of the FOV rather than the center of the FOV.
2. For the first half of the training process, use the --> key to move the target back to its original far-left position.
3. For the second half of the training process, use the <-- key to move the target to a point to the right of the starting position. To begin with, try moving the target to the point midway between the center and the right edge of the FOV.

It will require some experimentation to determine how far to the right of the original target position you should move the target with the <-- key. Too far to the left and some vestige of the original problem will appear. Too far to the right and the drive will not take up the slack in the drive train in time to compensate for terrestrial rotation.

Altitude training may be performed in the normal fashion.

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