More Instrument Rotator Clarification

Wednesday, March 14, 2018 12:30 PM

Problem(s) Encountered:

I sent the rotator to PA=0 according to the display, but I could see that the instrument was pretty far from the normal position. I aligned the peg with the fiducial mark and the display read 23 degrees. I reset the rotator angle in the TCS software to be zero at this position, but I don''t know how precise it is. I wasn''t able to successfully test it on-sky afterwards due to weather, but I did rotate it to +90 and back down to zero and the peg stayed aligned with the fiducial.


Here''s a time-saving tip for all you Trouble Report fans out there.  If you''ve moving to a new target and need to rotate,

1) Slew to a position near the zenith, but near to the azimuth of your target.

2) Rotate the instrument -- note that the dome is moving

into position while you''re doing this!

3) Set on your target.

In step (1), note that using the middle mouse button in

JSkyCalc sets the program coords to the position of the cursor,

so you can eyeball a position at nearly the same azimuth as

your target; then just "Coords->TCS next object" and initiate

the slew. [Thorstensen]