20170302

Twilight Tests

Note: Twilight exposures are critical science calibrations for LRS and VIRUS and if possible should be done every night that science data is taken.

twilights with VIRUS with different tracker positions

Purpose: There is some interest in seeing what the long term illumination correction changes look like including what different track positions do to them. The script is "specialtwilight" in /home/mcs/astronomer/bin/. It takes a single argument which is the Observation number.

Procedure:

• Despite of pressures at the start of the night try to get the twilights.
• Setup the guide camera for sky twilight (GC2, 0.1 sec, B filter)
• When you hit the correct flux level (biased to a slight higher value, perhaps 5k) execute the specialtwilight script

On-sky science:

We have a few changes in procedure that are important to note:

1) Use shuffle_config_matt5 this includes the new fplane file with the easy changes Karl wanted.

2) For LRS2 and LRS2+parallelVIRUS use vlexp code as per normal.

3) For VIRUS hetdex fields please use the $HET_SRC_ROOT/integration/hetdex-dither.py script which has the new guider dither method built into it. Note you will have to put in the actual observation number. We hope to update vlexp in the near future. You should look at the help pages to remind you how to specify observations. Here it is repeated for your reading:

$HET_SRC_ROOT/integration/hetdex-dither.py -h
usage: hetdex-dither.py [-h] -o OBS -O OBJ [-e EXPT] [--dry-run]

Execute a 3-dither HETDEX observation.

optional arguments:
  -h, --help            show this help message and exit
  -o OBS, --obs OBS     Observation number.
  -O OBJ, --object OBJ  Object descriptor.
  -e EXPT, --exptime EXPT
                        Exposure time per dither in s. Defaults to 360s.
  --dry-run             Print actions without executing commands on the
                        hardware 

Watch out for the moon brightness at the start of the night. I am not sure that the automatic moon brightness works in htopx so you should set this manually to make sure you don't hit inappropriate targets or miss targets. After the moon sets just turn off the moon brighness.

If you have a choice of targets please skip PSU17-1-002, however, if the moon is up these are perfectly fine targets to observe.

During any thin parts of the night (few targets) please try to get your standards.

When VIRUS targets are available they generally should have priority over regular targets, at least at the same priority.

Watch out for the request telluric standards needed just before or after UT17-1-008!

On-sky engineering:

This should be the lowest priority but could be done when the moon rises or during a hole in the queue (after standards have been taken). The priority of the tests is in the order given below.

Globular cluster dither test with VIRUS

Purpose: Now that we have eliminated some of the drag problems we would like to test how dithering looks on VIRUS. Do this on a globular cluster (GC). Choose a a very rich wide GC. Want to put the center of the GC on one of the currently active IFU.

Good globulars that we have used in past, that are up now, are:

NGC2419 (probably need 5 minute exposure for this) NGC4147 NGC5024 = M53 NGC5272 = M3

NGC5024 and NGC5272 would be ideal for this even though they are only in the East and CCAS will block some of the light.

• Use do_shuffle to set up on a globular cluster on one IFU
• Have TO setup guiding on gc1. This will put the guide probe close to the IFUs and will minimize the guider drag.
• offset the nearest bright star onto the BIB with the probes=true option.
  • It is critical that you get a star on the BIB for this test.
• while at dither position 1, start saving bib images (you may have to manually open the PFIP shutter) and get the proper exposure time (try to get exposure x coadd >= 3)
• start saving bib images
• record start time in the log
• Run take a parallel exposure with 120 seconds, virus as the prime and dither = true.
• when dither 3 is complete stop saving bib images
• record end time in the log
• setup on the next IFU.

repeat with gc2 to maximize the drift.

Here are some suggestions that might help.

antigc1
mgp -cp

convert /home/mcs/astronomer/matttmp/ACAMimages/ngc5024_103_E.png /data1/nossy/www/html/noss/htopx2/acam_dss.jpg
syscmd -T -v 'load_trajectory(id=4018, ra=13.2169, dec=18.298265, equinox=2000.0, dir="EAST" )'
syscmd -T -v 'Guider1_set_position( ra=13.2134, dec=18.151206 )'
mgp -mp
echo "starting ngc5024_103" >> mattlog
date >> mattlog
vlexp -i virus -t sci -texp 120 -pobj ngc5024_103 -sobj ngc5024_103 -dither -B
echo "ending ngc5024_103" >> mattlog
date >> mattlog

Closed dome:

Please look at the long cals and see if there are any that need doing.

[​https://hettrac:8001/trac/WFUCommissioning/wiki/NightOperations/SciencePlans/longcals ]