Problem(s) Encountered:

The guider seems to be having problems in what I think is the  N/S (Dec)

direction. The problem is indicated on the  X  strip chart but I think it is actually the Y direction, if the orientation is the same as the display.  Twice, the guide star clearly was displaced by several arc-seconds, and the guider was unable to bring it back.  Based on the motion of the image when I move the telescope by the paddle I believe up/down (Y) corresponds to S/N.  Perhaps this is related to the drift in the images we have noticed occur over the night, despite guiding?  One small annoyance with the guider software is that the  calibration  routine does not actually bring the guidestar back to its original position, but leaves in N of where it found it, so you lose your place if you calibrate in the middle of a series of integrations.

Solutions:

With respect to calibrating the guider, it really should only be necessary to do this once at the beginning of the run if it is behaving correctly.

About the guider not being able to move in the N/S direction (X-direction on the graph).  I have seen this before and I think it is related to the preload.  There is a lot of backlash in the N/S direction, and when it gets out of adjustment, short guide pulses will not move the telescope at all.  This problem was more obvious in the old days when you had to make fine adjustments with the physical hand paddle.  But it should be possible to see the same effect if you try to make small motions with the software paddle.  Try to move 1 arcsecond N/S/ with the software paddle and see what happens.

I don''t believe that this is related to the slow drift of the images over a period of hours.  We think that is some sort of flexure in the guide probe.