| 277 | 277 | 1. At start of night, check telescope pointing and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane). When taking the image of the bright star, make sure to create an OBJECT script with NGUI (not a TEST, because MOSSTAT will ignore it), zd filter, 1 - 5 sec exposure. Watch for MOSSTAT to process the image and report the RA, Dec offsets. If mosstat fails, it could be because (a) the telescope is mis-pointed, (b) the telescope is out of focus (set the focus approx using the formula above and try again). Once you are able to determine offsets, give these offsets to the OA with **opposite** sign. That is, if mosstat reads "RA,Dec offsets = -15.34, 18.32", then you need to provide the OA with the offsets of +15,-18 to zero the telescope coordinates. You can take another OBJECT frame if you want to check to make sure the offset went in the right direction. |
