LATISS Daily Calibrations BIAS, DARK and FLAT: all filters + empty#

Overview#

This procedure will enable and turn on the ATWhiteLight that illuminates the dome flat screen. It will position the telescope and dome in the FLAT position, and will take BIAS, DARK, and FLATS calibrations images in all installed filters including the empty filter. Finally will turn off the white light and send the ATWhiteLight to STANDBY. After the entire script completion, the telescope and dome will remain in ENABLED state and in the FLAT field position. The observer can decide whether to vent, proceed to on-sky or shutdown.

This page assumes the reader is familiar with the content explained in the Observatory section: Introduction to the combined calibrations generation procedure

Warning

This procedure involves telescope motion with AuxTel. Be sure to confirm the dome is clear of personnel and announce that you are going to run the calibrations with telescope movement on the #summit-announce and #summit-auxtel channels before you run the following steps. The whole process takes about 1.5 hours.

Post-Condition#

  • Individual calibration images will be taken and verified using the cp_verify framework.

  • If generate_calibrations is True, a (daily) combined calibration image per detector will be certified in a butler CALIBRATION collection.

Procedure Steps#

  1. Calibrations images should only be taken if the LATISS WREB temperature is under temperature control. Check the LATISS WREB temperatures under the AuxTel (LATISS) Temperatures and Pressures dashboard in Chronograf. WREB temperatures are visible in the lower middle panel labeled WREB On Board. If the mean_temp2 (top blue line) is between 26-29 degress C, the temperature is suitable for taking calibrations. During the daytime, the fan on the WREB board may not be sufficient to cool the WREB down to these temperatures, so during warmer months you may have to wait until later in the day or early in the morning for it to reach the desired temperature. If the temperature is too high, do not proceed to the next steps.

  2. Enable ATCS and LATISS using the standard scripts enable_atcs.py and enable_latiss.py with no configuration.

  3. Enable Scheduler:2 with a valid scheduler configuration. Use the standard script auxtel/scheduler/enable.py with the configuration required for the run and available in the corresponding night log.

  4. Run the script add_block.py to the ATQueue with the following configuration:

add_block.py#
id: latiss_daily_calibrations

The BLOCK with latiss_daily_calibrations configuration will queue the following scripts:

The BLOCK will start with the set_summary_state.py script to enable ATWhiteLight CSC with the following configuration:

set_summary_state.py#
data:
   -
     - ATWhiteLight
     - ENABLED

The set_summary_state.py script will enable OCPS:1 CSC.

set_summary_state.py#
data:
   -
     - OCPS:1
     - ENABLED

The SAL script auxtel/calibrations/power_on_atcalsys.py with no configuration inserted into the BLOCK latiss_daily_calibrations structure will start the chiller, turn on the white light and open the shutter. This script takes 15 minutes to complete, the time it takes to warm up the white light. On Chronograf using the query lsst.sal.ATWhiteLight.logevent_logMessage.message, the lamp reports its retry loop status explicitly.

auxtel/calibrations/power_on_atcalsys.py#

The auxtel/prepare_for/flat.py script (empty configuration) will position the telescope and dome in FLAT position. The telescope will point towards the dome flat screen (mount Az = 188.7 deg, mount El = 39.0 deg, dome Az= 2.59 deg). Confirm in the cameras aux-cam01 or aux-cam02 that the white light is on, and telescope is pointing to the dome flat screen.

auxtel/prepare_for/flat.py#

Depending on which filters are currently installed in LATISS, the auxtel/make_latiss_calibrations.py script may take different calibration sets. The calibration images displayed in RubinTV are post-ISR images and should have BIAS and DARK corrections applied. This means that BIAS and DARK images should display with maximum count rates of about 10 ADUs. In the case of FLAT images, counts must be below the \(\approx\) 30000 ADUs. In the process of building the daily PTC (see below), the FLAT saturation is intended, and achieved at around the 123000 ADUs (with exposure time of about 25 seconds). The daily FLATS reach values of \(\approx\) 68000 ADUs. If you see large deviations from these values, which can be related with a problem in the instrument signature removal in RubinTV, then RAW count rates are being displayed, please report it. Check the calibration sets and their configurations for each filter installed and the grating.

  1. : Set configuration for SDSSr_65mm.

auxtel/make_latiss_calibrations.py#
  n_flat: 20
  exp_times_flat: 6
  script_mode: BIAS_DARK_FLAT
  filter: SDSSr_65mm
  grating: empty_1

  1. : Set configuration for SDSSg_65mm.

auxtel/make_latiss_calibrations.py#
  n_bias: 3
  n_dark: 3
  exp_times_dark: 6
  n_flat: 20
  exp_times_flat: 6
  script_mode: BIAS_DARK_FLAT
  filter: SDSSg_65mm
  grating: empty_1

  1. : Set configuration for SDSSz_65mm.

auxtel/make_latiss_calibrations.py#
  n_bias: 3
  n_dark: 3
  exp_times_dark: 6
  n_flat: 20
  exp_times_flat: 3
  script_mode: BIAS_DARK_FLAT
  filter: SDSSz_65mm
  grating: empty_1

  1. : Set configuration for SDSSy_65mm.

auxtel/make_latiss_calibrations.py#
  n_bias: 3
  n_dark: 3
  exp_times_dark: 6
  n_flat: 20
  exp_times_flat: 30
  script_mode: BIAS_DARK_FLAT
  filter: empty_1
  grating: SDSSy_65mm

  1. : Set configuration for empty_1.

auxtel/make_latiss_calibrations.py#
  n_bias: 3
  n_dark: 3
  exp_times_dark: 1
  n_flat: 20
  exp_times_flat: 1
  script_mode: BIAS_DARK_FLAT
  filter: empty_1
  grating: empty_1

  1. : Set sequence for the daily Photon Transfer Curve (PTC). Skip it if the previous sets were queued manually.

auxtel/take_image_latiss.py#
  image_type: FLAT
  filter: SDSSr_65mm
  grating: empty_1
  reason: daily_PTC
  exp_times:
          0.25,
          0.25,
          1.42,
          1.42,
          6.53,
          6.53,
          4.23,
          4.23,
          30.04,
          30.04,
          12.56,
          12.56,
          57.75,
          57.75,
          8.13,
          8.13,
          2.73,
          2.73,
          3.40,
          3.40,
          1.77,
          1.77,
          111.03,
          111.03,
          37.35,
          37.35,
          0.48,
          0.48,
          0.59,
          0.59,
          10.10,
          10.10,
          1.14,
          1.14,
          0.20,
          0.20,
          89.29,
          89.29,
          71.81,
          71.81,
          0.38,
          0.38,
          0.31,
          0.31,
          19.43,
          19.43,
          2.20,
          2.20,
          15.62,
          15.62,
          0.92,
          0.92,
          0.74,
          0.74,
          24.16,
          24.16,
          5.25,
          5.25,
          46.44,
          46.44

  1. : Set sequence for daily_flats.

auxtel/take_image_latiss.py#
  image_type: FLAT
  filter: SDSSr_65mm
  grating: empty_1
  reason: daily_sflat,
  exp_times:
                  0.5,
                  0.5,
                  0.5,
                  0.5,
                  0.5,
                  12.8,
                  12.8,
                  12.8,
                  12.8,
                  12.8

The BLOCK with latiss_daily_calibrations configuration finishes with the auxtel/calibrations/power_off_atcalsys.py SAL script with no configuration. It will turn off the lamp, close the shutter and shutdown the chiller. At this stage, the script completion time is 15 minutes.

auxtel/calibrations/power_off_atcalsys.py#

Finally, the set_summary_state.py script sends ATWhiteLight back to STANDBY.

set_summary_state.py#
  data:
 -
   - ATWhiteLight
   - STANDBY

Once this last script is done, check the camera to make sure the white light is off. At this point, ATCS and LATISS are in ENABLED state and the dome and telescope are in FLAT position.

Note

The location of the BLOCK source code can be checked and if the filters or exposures times have changed, create a ticket for yourself and edit this document accordingly.

Contingency#

In cases such as telescope and dome movement not allowed or not cleared, or not enough time available for calibrations, skip this procedure.

This procedure was last modified Jun 17, 2024.