MDM Trouble Report for 2018 Sep 12

Telescope: 2.4m
Observer(s): Weil (Dartmouth)
Instrument: OSMOS/B

Problem(s) Encountered:
I had problems with the temperature dependant focus corrections. 
Based on the focus number printed in the TCS, I adjusted the 
target focus position for the relative differences when changing
filters. Image quality slowly decreased during the night despite
the focus numbers changing with the temperature differences. 

To check the problem I ran a full focus test and found
that the focus was higher by about 100 units
than what the values should have been based on the temperature
changes during the night. 

In addition, after disabling the temperature 
compensation system, the focus shown on the TCS decreased by the
amount that had been shown in the adjustment box before disabling it. 

After resetting the target position again, and running another 
focus test, the new focus numbers remained 100 units higher than 
what they should have been based on the temperature and earlier 
focus tests. 

As a result of this, I finished the night without using
the automatic focus temperature compensation and
manually adjusted the focus with temperature. 

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Submitted on 2018 Sep 13 [5:11:00]