Telescope Focus Failure Revisited

Friday, April 13, 2018 2:15 PM

Problem(s) Encountered:

I was unable to adjust the focus entirely. I attempted to perform the focus4k routine in Prospero at the beginning of the night, but the focus hung up when it was going through the early stages of the routine. I tried using the hand paddle, TCS, and Prospero to pull it out of its hangup, but none of that worked. I powered cycled the driver chassis and closed and reopened all of the data acquisition windows (ISIS, Caliban, etc). Still no good. Basically lost the entire night as a result. I sent an email to DFM who will hopefully get back to us tomorrow during the day.


Was able to get the telescope to change focus position initially.  Decided to test out the entire system, running from limit-to-limit.  Upon hitting the “IN” (upper) limit, the focus halted and I could no longer move the motor in either direction.  Pulled the drive belt and moved off the limit by hand but still could not get the motor to turn at all.  Contacted DFM and found that a bug in the code caused the galil thread to crash and not be revived under certain circumstances, including when hitting a limit.  This was corrected and the system brought back online.  Focus now appears to function fine again.

I have an uneasy feeling about the focus drive motor for some reason and may procure a spare just to have on-site to quickly swap if need ever arises.

Incidentally, instrument focus positions lay well within either limit switch thankfully.