MDM Trouble Report for 2018 Jan 12

Telescope: 2.4m
Observer(s): Douglas (Columbia)
Instrument: OSMOS/R

Problem(s) Encountered:
The focus drift issue happened again, at least with the numbers on the TCS window.
The obvious focus drift in in terms of PSF size/shape wasn't as bad as last night, though; 
I assume some of that last night must have been caused by temperature changes. I 
tracked the numerical focus in the TCS window throughout the night, so I can provide
that if it will help. 

Also, JSkyCalc and the TCS bridge didn't seem to be reading the telescope position 
automatically, or updating any outputs. I had to click read telescope/refresh output/set 
to now frequently. I imagine I just need to restart them, and I'll try that tomorrow when I'm 
more awake; in the course of the night it was easier to just click the buttons rather than 
risk taking longer to fix it. 

My major issue tonight was some combination of the guider and pointing, and I'm 
honestly not sure how much of the issue was one or the other. Twice, I slewed to a star 
and got a guide star set up, but when I took a sky image the pointing was clearly off. 
When I slewed to try to center things, I ended up 20-30 arcsec north of where the object 
was supposed to be. 

At the same time (in both cases) the guider also had issues. JSkyCalc wasn't 
reading the correct guider position (i.e., I'd send it to origin but JSkyCalc thought 
it was still at the old guide star), it clearly wasn't going to the right position (i.e., there 
should be 2-3 stars close together at that position, but I can only see one),
and when I tried to send it to origin I got the  not at X CCW limit  warning. 

The first time this happened, I kept sending the probe back and forth between origin,
center, and a guide star, both at the target I was trying to observe and eventually a 
nearby bright star. Somehow this seems to have reset the guider, at least, and it started
to go to the right place. The initial pointing on a star was a tad East after that, but that 
eventually resolved itself too. I spent about half an hour trying to figure out what was
going on. 

The second time, the pointing was even farther off, and it was again very clear that the guider
wasn't on the right guide star. After sending the probe back and forth to the origin and 
center, I quit xmis and power-cycled the MIS. This resolved the X limit error, but 
not the pointing error. I slewed to a nearby bright star, the pointing was spot on. I slewed
back to my target, and the pointing seemed closer to correct. I started tracking a 
guide star again, and tried to calculate an offset with the slit. The offset kept changing,
asking me to move (+21, +23), then (-10,+5) from the updated position, and then another
similar move of 10s of pixels (I didn't write it down). I was >30  from the star's
nominal position at that point. 

I stopped guiding and sent the telescope back to zenith. I went to the  nearest bright star, 
and it centered up pretty well. I slewed back to the cluster and the pointing was OK. 
It took me an hour or so to deal with this second error. 

------------------------------

Submitted on 2018 Jan 13 [7:41:18]