Changes between Version 97 and Version 98 of PublicPages/MayallZbandLegacy/NotesforObservers

Timestamp:

Feb 13, 2016 6:29:17 PM (8 years ago)

Author:

Arjun Dey

Comment:

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PublicPages/MayallZbandLegacy/NotesforObservers

@@ -246 +246 @@
 
 1. Take a zero image to ensure everything is working
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 2. Set the focus to some approximate value based on the Truss temperature and the formula: 
 - Focus(zd) = -8400+(1.4-Ttruss)x110
 where Ttruss is in deg C
+
 3. 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.
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 4. Move to the beginning of the first MzLS tile position.  What position is that, you ask?  One way to find out is to run mosbot.py (see step 5 below), and look for RA, DEC in expose-1.sh in the exec/mosbot/ directory.  Tell these coordinates to the OA to move the telescope. Another way is to look at teh first entry in the ~/obsbot/pass1.json file on the mayall-idl computer - remember, it is in degrees, so you will have to divide the RA by 15. Getting within a degree is close enough, so no need to be super precise.
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 5. Focus the telescope
  - create a focus script using the NGUI: exposure time 5 or 10 seconds, zd filter, -100 micron focus steps, click Midpoint to *on*, 9 exposures.