VIRUS Alignment Characterization Procedures

Updated in 2021: full-array VAC data acquisition

Our usual approach now is to take data for the full array in a sequence of exposures. The script for this is found in /home/mcs/astronomer/stevenj/vac_set_2021_08.sh and takes about 4.5 hours to complete.

After taking data, send an email to het-vac@het.as.utexas.edu following this template:

• subject:

  full array VAC data taken
  

• body: (adjust as needed to be accurate)

  A full set of VAC data were taken on YYYY-MM-DD UT.
  
  7100: 15x bias
  
  7101: 9x Hg (2.5s)
  7102: 9x Cd-A (18s)
  
  7103: 9x Hg (4.2s)
  7104: 9x Cd-A (30s)
  
  7105: 9x Hg (7.1s)
  7106: 9x Cd-A (49s)
  
  7107: 9x Hg (11.9s)
  7108: 9x Cd-A (81s)
  
  7109: 9x Hg (20s)
  7110: 9x Cd-A (133s)
  

Older notes follow below

Goal

The goal is to take 5 unbinned Hg lamp exposures, 5 dark frames (with same PFIP exposure time), 5 unbinned Cd-A lamp exposures, 5 dark frames (with same PFIP exposure time), and 5 bias frames to test the alignment of newly installed VIRUS units once these units have been stable and cold for (at least) 16 hours. The Hg and Cd-A lamp exposures need 45-55k in the peak line on the target IFUs. The dark frames should be the same exposure times as the lamp PFIP shutter exposure times (not the FCU exposure time).

Note we are trying to use the same numbering for engineering tests so for the test exposures please use the 6000s and the final VAC exposures please use 7100-7199.

The VG and IP must be OFF while taking the data for this test.

Note exposure times for Hg and Cd-A need to be checked every time for new IFUs. Listed below are the exposure times from previous dates/units.

Reporting

When you have completed a successful set of VAC, email het-vac@het.as.utexas.edu with the following information:

• The email subject line should include 'VAC' and the V-number in the format 'Vnnn'

• The email body should include:
  • the yyyymmdd of the data directory
  • the observation numbers for each of the bias, Hg, and Cd data. These should be:
    • 7100 for Bias
    • 7101 for Hg
    • 7102 for Cd
    • 7103/4 for Dark if required

Results

UT Date	IFU(s)	Hg exp time [s]	Cd-A exp time [s]
20190504	S081/V327, S105/V051	8.8	60
20190524	S072/V405	4	35
20190528	S072/V405	4	30
20190529	S097/V405, S072/V017	5.4
20190529	S072/V017		45
20190529	S097/V405		33
20190712	???	2.4	30
20190719	S041/V407,S077/V402	2.5	20
20190819	S031/V408	8.0	45
20190915	V409,V410,V330	8.0	60
20191009	V411	10.0	62
20191011	V330	8.5	50
20191017	V410, V412	9.0	53
20191022	V413, V414, V330	9 (V413), 6	65 (V413), 48
20191031	V410	9	81
20191105	V317	10.3	80
20191128	V410, V415	9 (S015), 3.5 (S048)	70 (S015), 25 (S048)
20191130	V410, V415	9 (S015), 3.5 (S048)	70 (S015), 24 (S048)
20191209	V401, V417	3.2	25.5
20200207	S069/V421	10	90
20200211	S057/V418, S058/V416	5	47
20200314	S078/V422	8.5	90
20200315	S030/V420	45	480
20200412	S089/V423 S039/V424	24	236(V423), 303(V424)
20200414	S049/V425	20	200
20200427	S078/V422, S039/V424	11,31	134,300
20200623	S061/V427	21	207
20200624	S024/V317, S034/V305	36,14	333,129
20210326	S069/V421, S077/V402	4.5	25
20210513	S070/V502	17	125
20210514	S080/V501	23	160
20210522	S097/V505	7	48

New script (testing mode for now, not verified to work)

Run ~sir/dev/astro/operations/virus_tests.sh <vac|dsf> [-skipip]

"skipip" only if you do not need that script deal with IP and VG.
Script first warm up lamps and entering test mode to determine correct exposure time. It will ask for max flux level after each test exposure and will display corrected exposure time. Available commands are:

nextifu next IFU
next next lamp
quit exit the script

Scripted commands

Note about testing exposure times:

• In testing that the brightest arc line is in the range 45-55K, just replace "-L 5" with "-L 1" in the script commands below so that you take a single image at a time.

Note on naming scheme:

• for binning 1x1 name will be "unbinned_<lamp name>"
• for all other non standard binning scheme are : "<lamp name>_<binning>"

Commands (it's recommended to run each command with "--dry-run" first for checking):

First step is to determine appropriate exp time for Hg and Cd-A to get 45-55k in the peak line on the target IFUs. Do this using observation numbers 6XXX and start with exposure times about half of those given above in case you saturate.

Try the following for faster work if during dark dome conditions:

Turn on the Cd-A and Hg lamps through the TCS gui

ipvg off -V
countdowns 780

Cd-A test exp vlcal -i virus --binning 1x1 -l cd-a -L 1 -bexp 55 -o 6101 -skip_warmup -B
Verify the Cd-A lamp is on and warmed up, and calculate the correct exposure time for the VIRUS unit of interest to get 50k peak.
Hg vlcal -i virus --binning 1x1 -l hg -L 1 -bexp 7 -o 6102 -skip_warmup -B
Verify the Hg lamp is on and warmed up, and calculate the correct exposure time for the VIRUS unit of interest to get 50k peak.
Now run the following but remembering to change the exposure times!!!

• vlcal -i virus --binning 1x1 -b 5 -o 7100 -skip_warmup -B
• vlcal -i virus --binning 1x1 -l hg -L 5 -bexp 9 -o 7101 -skip_warmup -B
• vlcal -i virus --binning 1x1 -l cd-a -L 5 -bexp 20 -o 7102 -skip_warmup -B
• ipvg on -V

If dome lights are on (Note: -skip_warmup option is not in use, will need to wait for warmup for each set, also with lights on darks are taken for each lamp exposure time):

• ipvg off -V
• biases vlcal -i virus --binning 1x1 -b 5 -o 7100
• Hg vlcal -i virus --binning 1x1 -l hg -L 1 -bexp 2.5 -o 7101
• Cd-A vlcal -i virus --binning 1x1 -l cd-a -L 5 -bexp 30 -o 7102
• darks vlcal -i virus --binning 1x1 -d 5 -de 20 -o 7103
• darks vlcal -i virus --binning 1x1 -d 5 -de 30 -o 7104
• ipvg on -V

To judge the image flux levels

Use the virusview command to view the images from all 4 amps of a given S###. Measure the peak flux in each amp using the ds9 Scale histogram (Scale Parameters). Use the most sensitive amp to judge the max peak level. Use this level to estimate the exposure time needed to achieve a peak of 50K or so.

Example of BAD data

Verify that your exposures do not look like the one shown below. In that case, a probe was partially blocking the light reaching this unit. Move the offending probe until the unit is not vignetted.

Low level commands

To take the bias frames one could do the following:

syscmd -V 'expose(seconds=0, x_binning=1, y_binning=1, type="zro", object="unbinned_bias", observation=7100, exposure=1 )'
syscmd -V 'wait_for_write(observation=7100,exposure=1)'
syscmd -V 'expose(seconds=0, x_binning=1, y_binning=1, type="zro", object="unbinned_bias", observation=7100, exposure=2 )'
syscmd -V 'wait_for_write(observation=7100,exposure=2)'
syscmd -V 'expose(seconds=0, x_binning=1, y_binning=1, type="zro", object="unbinned_bias", observation=7100, exposure=3 )'
syscmd -V 'wait_for_write(observation=7100,exposure=3)'
syscmd -V 'expose(seconds=0, x_binning=1, y_binning=1, type="zro", object="unbinned_bias", observation=7100, exposure=4 )'
syscmd -V 'wait_for_write(observation=7100,exposure=4)'
syscmd -V 'expose(seconds=0, x_binning=1, y_binning=1, type="zro", object="unbinned_bias", observation=7100, exposure=5 )'
syscmd -V 'wait_for_write(observation=7100,exposure=5)'

Now take the lamp exposures (Note that the exposure time of 8.8 seconds has previously worked well for the brightest emission line for the S105 unit but might not be good for future units Try taking a test exposure with observation=6xxx.

Also note that the flux level of the Hg lamp does not fully stabilize until 13 minutes after it has been turned on.

ipvg off -V
syscmd -P 'FCUDeployHead()'
syscmd -P 'FCUEnableLamps(lamps="Hg",slider="a",state="on")'
sleep 180
syscmd -P 'FCUExposeSliderA(time=0.1,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="cmp", object="unbinned_Hg", observation=7101, exposure=1 )'
syscmd -P 'FCUExposeSliderA(time=8.0,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'wait_for_write(observation=7101,exposure=1)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="cmp", object="unbinned_Hg", observation=7101, exposure=2 )'
syscmd -P 'FCUExposeSliderA(time=8.0,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'wait_for_write(observation=7101,exposure=2)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="cmp", object="unbinned_Hg", observation=7101, exposure=3 )'
syscmd -P 'FCUExposeSliderA(time=8.0,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'wait_for_write(observation=7101,exposure=3)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="cmp", object="unbinned_Hg", observation=7101, exposure=4 )'
syscmd -P 'FCUExposeSliderA(time=8.0,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'wait_for_write(observation=7101,exposure=4)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="cmp", object="unbinned_Hg", observation=7101, exposure=5 )'
syscmd -P 'FCUExposeSliderA(time=8.0,lamp_name="Hg",headpos="overide",light_guide="blue",shutter="virus")'
syscmd -V 'wait_for_write(observation=7101,exposure=5)'
syscmd -P 'FCUEnableLamps(lamps="Hg",slider="a",state="off")'
syscmd -P 'FCURetractHead()'

To take the dark frames: (at the PFIP exposure time)

syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="drk", object="unbinned_dark", observation=7103, exposure=1, dark="true" )'
syscmd -V 'wait_for_write(observation=7103,exposure=1)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="drk", object="unbinned_dark", observation=7103, exposure=2, dark="true" )'
syscmd -V 'wait_for_write(observation=7103,exposure=2)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="drk", object="unbinned_dark", observation=7103, exposure=3, dark="true" )'
syscmd -V 'wait_for_write(observation=7103,exposure=3)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="drk", object="unbinned_dark", observation=7103, exposure=4, dark="true" )'
syscmd -V 'wait_for_write(observation=7103,exposure=4)'
syscmd -V 'expose(seconds=20, x_binning=1, y_binning=1, type="drk", object="unbinned_dark", observation=7103, exposure=5, dark="true" )'
syscmd -V 'wait_for_write(observation=7103,exposure=5)'

Then do the same for the Cd-A lamps, using #7102 (and if required, darks at the same exposure time using #7104)