MkIII Setup Hiccups

Wednesday, April 25, 2018 12:28 PM

Problem(s) Encountered:

The two main issues were that

1) the guider camera is far out of focus.  We were pushing the top guider focus button and it stopped improving (spot getting smaller) when we hit the end of the range. From where we started, we probably had moved about 1/3 of the way towards best focus, but still saw a fairly large donut.

2) it seems that the slit viewing camera may have been loose and/or had a mechanical interference, possibly with guide probe movement.  

We can see two slits, but as far as we can tell, neither is actually the entrance slit.  We tried to position a very bright star over both, but no light showed up on image.  We *think* this happened when the guide probe was moved towards a star near center of field, but it isn''t clear whether that was a coincidence.


Guider focus was moved to the inner limit.  I had adjusted the rough mechanics for the guide probe prior to setting up the MkIII as needed, but guess it was not adjusted as much as needed.  I’ve moved the rough adjustment further in and centered the motor-mic again, allowing for travel in and out.  Should be able to focus on a guide star now.  It should be noted however that even on a donut, the system is robust enough that guiding is possible.

The issue with the slit-viewing camera boils down to setup error.  The camera optics were pushed in and focused on a slit.  The issue though is it was the wrong slit.  Using the linear array of pinholes at the end of the slit plate, I aligned the Andor optics to look down at whichever slit is in the instrument path.  I then verified that I was indeed looking at the smallest slit option (requested).  Should be good to go.