Motion Failure and more...

Friday, January 25, 2019 11:09 AM

Problem(s) Encountered:

The initial symptom of the problem was that I could not slew to targets using JSkyCalc13m.  It worked for my very first field, but failed after that.

I shut down and restarted both JSkycalc and the TCS panel, but that didn't help. The TCS appeared to be running (the software was responsive, gave sensible outputs, and the telescope could move with the  point  command).  However, JSKyCalc13m did not slew the telescope.  I picked a target from my list and selected  Slew Telescope  and eventually I got an error  Slew failed  after no movement occurred.   I did a telescope stop and start and that did nothing.

Eventually, after some troubleshooting, the dec stopped responding altogether and I couldn't home it, so I went down to the 1.3m and checked out the Dec controller.  It was displaying an error, so I cycled the power.  After that, I could move.  

Somehow in this process we lost good pointing, so I had to go to zenith, use the tiltmeters, and re-zero the pointing.  After that, the telescope behaved normally.


A slow fail like this is sort of new.  Glad you were able to reset the controller and get on-sky.The pointing issue is a known mystery to me that occurs whenever the servers are cycled (and the TCS GUI is refreshed).  For some reason, at zenith the encoders default to HA=00:00:12 and dec=48:00:00.  I have no idea why this happens.  A simple zero command can reset the encoders to known values.