Observing Plan for the October 22 2013 Engineering Night

Proposal Id: 2013A-9999
Exposure Scripts: Most of the exposure script for this night are available in ~DECamObserver/ExposureScripts/engineering_20131022
(from the Observer Console GUI select Exposure Control --> Load Exposure Script --> Choose File)

(Late) Afternoon

Full set of zeros and dome flats
Script: prenight_calibration.json (note that this is a (standard) DES script. From the the Observer Console GUI select Exposure Control --> Load Exposure Script --> Select DECam Script then choose DES/prenight_calibration.json in the dialog window)

PTC (Afternoon)

In the afternoon we need to run the photon transfer curve script PTC_r.json.
This is a standard DES script so it can be loaded from the Observer Console GUI in the same way as the prenight_calibration script.

Linearity Study

We will take exposures of a rich star field in g band with a range of exposure times, so we can test that the linearity corrections derived from dome flats are properly correcting the sky data. Instructions are:

  • Move to the desired field (see coordinates below) and put the g filter in the beam. AOS and guider turned on.
  • Start script ??? to take series of 45 exposures of different exposure time at same pointing. Should take 40 minutes.
Options for coordinates to use for this test, in order of decreasing preference:
  • 20:40 -35, (galactic +8, -36) which is at decent airmass until roughly 0230 UT. The moon would be down for this, gives us the best S/N and best test of low-sky-level linearity.
  • 07:30 -50 (galactic 262, -15), available after 0700 UT
  • 06:40 -34 (galactic 243, -17), available after 0600 UT

This test requires photometric conditions. Don't bother if clouds are visible in the sky.

Guider CCD astrometry

Use a special readout mode to save long-exposure data from the guider CCDs so that we can determine their astrometric solutions relative to the science array to better than 1". There will be 2 components needed for this test:


During the daytime, take zeros and dome flats in each filter using the normal dome-flat exposure times, but with SISPI instructed to save the guider readouts.
The guider calibration script is called guider_zeros_flats.json and can be found in the engineering20131022 directory.
This script does not have the standard action commands to turn of vsub and such. Nor does it include the vsub flush exposures.
Before you run it you have to tell the GCS to use a different directory so that we can keep these images.
On the architect console select the GCS. Then, in the command box enter:

set image_directory /data_local/images/fits

Once this script is done you need to switch back using the command (again with the GCS selected)
set image_directory /dev/shm/guider

Also when you configure (or restart) the image directory is switched back. If the timing works out Klaus would like to be online for this to make sure it works.

Guider Exposures

During the nighttime, move to any one of the three coordinates given for the linearity test. Then take 3x20 s exposures in each filter, moving 1 arcmin N of original pointing for 2nd exposure and 1 arcmin E for 3rd exposure in each filter. The guider_astrometry.json script in the engineering20131022 directory is set up to do this.
Like in the previous test you need to switch the image directory so that the images are kept. Using the architect console select the GCS and enter:

set image_directory /data_local/images/fits

Once this script is done you need to switch back using the command (again with the GCS selected)
set image_directory /dev/shm/guider

SISPI Studies

Check out new features (most of this can be done in the afternoon):
  • Additional debug statements to help understand the "Missing CCDs" error and the Shutter Sync. problem
  • New action commands to control AOS from script
  • New relative focus keyword in exposure requests


Eric has prepared a new version of obstac that he'd like to check out. It basically comes down to see if obstac correctly schedules a wide survey exposure. Eric will be online early during the night and if necessary tweaks obstac to skip the SN fields. There is also a new version of Nightsum - to test this is would be good to go through the motion and to generate the nightly summary.

Calibrate Stars around BD+17 4708 (before midnight local time)

  • For today's date, the ideal time is around 10:00PM Local Time, when BD+17 is crossing the meridian and is at its lowest airmass (X~1.5)
  • Conditions must be clear; otherwise, skip this task
  • Observe a set of 3 standards fields (low-, intermediate- and high-airmass), make sure they include u-band standards
  • Then observe the attached json script (BD17_4708.json) to calibrate stars around BD+17 4708
  • Then observe a second set of 3 standard star fields (again include u-band)
  • The same task was performed on the night of 20 September 2013; for reference, here is that night's nightsum

AOS/Donuts tests

Test AOS script to take nightly out of focus image using new SISPI features.

AOS Test (about 1 hour). Requires seeing <1.2" and galactic plane visible (or other dense star region)

  • Move the telescope to a location with high stellar density (ideally galactic latitude around 15 degrees). Telops can usually assist with this. We will be tracking the same location on the sky for around an hour. Otherwise contact Kevin Reil ().
  • Run the script aos_focus_align.json - this will take 5 * 30 second 'r' band exposures to get the telescope in focus and aligned. (10 minutes)
  • Run the script aos_on_grizy.json - this will take 2 * 30 second exposures in focus for 5 (grizy) bands with the AOS on (normal operations). (20 minutes)
  • Run the script aos_defocus_grizy.json - this will take 2 * 30 second exposures out of focus (+1500 um) for 5 (grizy) bands with the AOS off. Camera will be refocused (to prior setting) at end of script. (20 minutes)

If at anytime the above plan is not working as expected, focus can be restored by clicking the "Init. z trim" button on the ICS/Hexapod control and running the aos_focus_align script.

Deep Y band observations, fringe tests

(from Peter Nugent and Paul Martini)


We'd like 60 Y-band exposures (each 90sec) to measure the amplitude of the fringe pattern. 10 dithered images per deep SN field and the corresponding 2 adjacent shallow sub-fields would be ideal, as that may be useful for calibration and photo-z work too. This should take a total of 2-3 hours.

  • Point at an SN field C1, C2, C3 and X1, X2 and X3. (coordinates are on this page: SN-C3 and SN-X3 are top priority
  • All of these fields are up in the second half of the night, they do not have to be directly overhead, secz < 2.0 is fine
  • Run the above json scripts (linked to field names) to take 10 exposures for each one, these are in a 3-4-3 pattern of equilateral triangles separated by 30" on a side. Please check these json files, it's my first attempt at them.
  • Repeat for the next field

Regression Script

Regression_Observations_All.json - the standard regression script - about 5- 6 hours