Now that I'm awake (sort of) I have some more information on my 201 problem.

The cables appear to be fine. I checked them with an ohmeter and tried
changing the RA tracking rate by 3% in each direction. In both cases the 201
guided out the RA error with a constant RA drift (east I think). The stars
were trailed slightly in RA, about 10 pixels. There was no error in dec,
although I was well polar aligned so I may not have seen any in the 5 minute
exposure.

The main camera was a 416XT on a Schmidt Newtonian with a focal length of
812 mm and the guiding setup was a separate guide scope of 900 mm focal
length. There was no relative motion between the scopes over the 5 minute
exposures as the drift shows up when I use an off-axis guider as well.

During the exposures the long axis of the 201 was aligned with RA. The 201
was in decent focus, I think. I am planning to do some more tests on the
next clear night, I will rotate the 201 by 90 degrees and see if the error
stays in the RA direction and I'll verify the focus. Ialso might increase
the focal length of the guiding scope with a barlow.

Can anyone think of any additional tests to do to find the cause of the
problem?

Blair

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