Problem(s) Encountered:

The drifting problem seen yesterday returned. The telescope would be tracking a target and suddenly would start drifting in RA. (I could see the RA changing on the TCS monitor.)  This happened both while guiding and when not guiding. RA was always increasing.  Sometimes it would just move a little bit and then stop for a while, but eventually it would just start drifting until a new movement command was sent to the telescope.  I was able to do some imaging with 2-3 minute exposures, but when I tried to do spectra or longer exposures it would start drifting before the exposure was complete.

This happened with the last 4-5 targets I attempted, and drifting typically started anywhere from 5-30 minutes after moving the telescope to the target.

Since I was unable to find a target that the telescope wouldn''t drift away from, with about an hour left until twilight and clouds getting thicker, I decided to close up for the night.

Solutions:

Knowing that the RA indicated the motion is a good data point.  It points towards mechanical issue.  Also, knowing about the squeak/squeal is a good thing.  In fact, I heard it this morning as well.  I lubricated areas that seem to have, in the past been sticking points (pun intended) and run the telescope.  Motions do sound much smoother although I could be tricking myself.  Regardless, numerous slews followed by leaving it to track showed no discernible change in RA, so that’s a good thing.

In regards to the bearing, I’m not ready to “go there” yet.  That said, I pulled the inspection plate off and took the chance to clean it out.  Visual inspection of the limited area that can be seen shows what appears to be a bearing in very good shape.

Now not much else to do except take a wait-and-see approach.