The vlexp command and output
Last updated: Nov21,2019



Description of the Nov2019 dither test

An set of engineering data was collected on 20191114. In this test we observed a random field at a relatively low galactic latitude using the same dither procedure used for VIRUS hetdex observations. Basically, after we execute the vlexp command to take the dithered VIRUS data, we move the acm mirror into the system and takes acm images for the duration of the dither sequence. 


Notes from 20191114_RAlog.txt:

Random target in f11 catalog:
target_setup 30989 E -cat f11 -ifu 000 -to

The coomand we ran:
vlexp -B -i virus -pobj Dither_Test -texp 20 -dither -np -vobs 7101 |& tee -a Adither.test

Here is the full Adither.test output  
------------------------------------
2019-11-14T10:42:06.257 INFO  [vlexp               :            : 372] - Attaching to VIRUS
2019-11-14T10:42:06.776 INFO  [vlexp               :            : 427] - Attaching to PFIP
2019-11-14T10:42:07.304 INFO  [vlexp               :            : 430] - Retracting ACAM pickoff mirror
2019-11-14T10:42:17.769 INFO  [vlexp               :            : 433] - Retracting CWFS/PV pickoff mirror
2019-11-14T10:42:17.772 INFO  [vlexp               :            : 436] - Set dither to position 1
2019-11-14T10:42:18.622 INFO  [vlexp               :            : 514] - Starting VIRUS dither exposure 7400 with guiders ['Guider1', 'Guider2']
2019-11-14T10:42:18.625 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:42:47.645 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T10:48:55.148 INFO  [vlexp               :single_exp          :  75] - Shutter is closed
2019-11-14T10:48:55.151 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider1 fiducial by dx -0.73 and dy 1.27 compensate is true
2019-11-14T10:48:55.155 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider2 fiducial by dx -0.73 and dy 1.27 compensate is true
2019-11-14T10:48:55.160 INFO  [vlexp               :single_exp          :  92] - Waiting for readout
2019-11-14T10:49:15.386 INFO  [vlexp               :single_exp          : 105] - Waiting for write
2019-11-14T10:49:30.306 INFO  [vlexp               :single_exp          : 117] - VIRUS exposure 7400:1 completed
2019-11-14T10:49:34.954 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:49:55.795 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T10:56:03.496 INFO  [vlexp               :single_exp          :  75] - Shutter is closed
2019-11-14T10:56:03.499 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider1 fiducial by dx 1.46 and dy -0.0 compensate is true
2019-11-14T10:56:03.505 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider2 fiducial by dx 1.46 and dy -0.0 compensate is true
2019-11-14T10:56:03.512 INFO  [vlexp               :single_exp          :  92] - Waiting for readout
2019-11-14T10:56:23.637 INFO  [vlexp               :single_exp          : 105] - Waiting for write
2019-11-14T10:56:37.154 INFO  [vlexp               :single_exp          : 117] - VIRUS exposure 7400:2 completed
2019-11-14T10:56:41.787 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:57:02.909 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T11:03:10.910 INFO  [vlexp               :single_exp          :  75] - Shutter is closed
2019-11-14T11:03:10.913 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider1 fiducial by dx -0.73 and dy -1.27 compensate is false
2019-11-14T11:03:10.917 INFO  [vlexp               :single_exp          :  88] - Offsetting Guider2 fiducial by dx -0.73 and dy -1.27 compensate is false
2019-11-14T11:03:10.920 INFO  [vlexp               :single_exp          : 116] - Skipping wait for readout and write for last exposure
2019-11-14T11:03:10.924 INFO  [vlexp               :single_exp          : 117] - VIRUS exposure 7400:3 completed
2019-11-14T11:03:10.925 INFO  [vlexp               :            : 528] - VIRUS dither exposure 7400 complete
------------------------------------
For the current experiment, we want to isolate the acm images taken at each of the three dither positions. These should emulate the sky positions "seen" by VIRUS during the observation sequence. The following command times will isolate these three positions: P1, P2, P3. 


P1:
2019-11-14T10:42:18.625 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:42:47.645 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T10:48:55.148 INFO  [vlexp               :single_exp          :  75] - Shutter is closed

P2: 
2019-11-14T10:49:34.954 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:49:55.795 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T10:56:03.496 INFO  [vlexp               :single_exp          :  75] - Shutter is closed

P3:
2019-11-14T10:56:41.787 INFO  [vlexp               :single_exp          :  59] - Exposing VIRUS for 360.0s
2019-11-14T10:57:02.909 INFO  [vlexp               :single_exp          :  67] - Shutter is open
2019-11-14T11:03:10.910 INFO  [vlexp               :single_exp          :  75] - Shutter is closed

What VIRUS "sees" is from the "Shutter Open" to "Shutter Closed" periods. 
Hence, the three important times intervals are: 
   P1     10:42:47.645  10:48:55.148
   P2     10:49:55.795  10:56:03.496
   P3     10:56:41.787  11:03:10.910



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