Alignment with Image Quality Info night of 111712¶
The BCAMs measure the position (x,y) and angle (tip, tilt) offsets of the hexapod from what it considers to be the optimal position and send the corrections to the AOS. These plots show the BCAM-measured offsets for the first part of the night on 11/17/12, when the camera and telescope were operating smoothly. If the hexapod were in the ideal position, the BCAM corrections would be zero. This is indeed the case for the angular offsets, which are well-measured by the donut system.
The x,y measurements show significant offsets, suggesting that the hexapod is mis-centered by several hundred microns or more in many positions. In this plot I've also included image-quality data from QuickReduce so that we can see if it depends on the hexapod displacement. There are some clear jumps in the SPT-W field that are probably tracking/guiding issues.The vertical lines represent different telescope pointings. They are:
- Standard field SDSSJ0000-0000 (dec = 0)
- Standard field C26202 (dec = -27)
- Standard field SDSSJ0320-0000 (dec = 0)
- SPT-W field (dec = -53; tracking is said to be especially good here)
- Mini-1a survey field (dec ~0)