Observing Plan for the January 14-15 2014 Engineering Nights

Proposal Id: 2013A-9999
Exposure Scripts: Most of the exposure script for this night are available in ~DECamObserver/ExposureScripts/engineering_20140114
(from the Observer Console GUI select Exposure Control --> Load Exposure Script --> Choose File)

Alistair will be observing (tbc)

Daytime activities

Cage covers fit check (Freddy)

Best done with the telescope flipped to F/8

LN2 lines 1s and 1r (Alistair)

Further attempts or do we leave this as is?

Oil Cooling

AC Installation

F/8 Tests

Are there any further F/8 tests?

(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)


We would like to repeat the star flats measurements in the grizY filter bands.

Instructions from Gary:

The best field to use for this would be the outskirts-of-Omega-Cen field we used last year, which is viewable at the end of the night. Earlier in the night you could use the 0730 field.

   RA=13:27 DEC = -48:45  
   RA=07:30 DEC = -50:00

There are 22 exposures in the sequence, so 5 x 22 x (30+30)s = 110 minutes to do this whole thing.

The pointing is not critical (1 arcmin accuracy is fine), but you will need to move the telescope back
to the starting position when beginning each filter.

If time is short you can omit one or more of the filters. The star flats should be done in clear weather, although seeing as poor as 1.5-2" will give data of at least some value. Better seeing is better...

The 5 scripts can be found in the engineering_20140114 folder. They are named Starflat<filter>.json_

Out of Focus Sky Map (Roberto)

Measure astigmatism on center CCDs in preparation of now 4maps control system.

  1. Turn off AOS (init_pid AOS_OFF using the Architect Console GUI)
  2. Set the z trim value to +1500 (Q: should the other trim fields be cleared? Should filter and temperature LUT be unchecked in the ICS/Hexapod GUI?)

Dome Position Tests

Suggestions from Gary for a test of how dome occultation affects the photometry:

  • Do not do this test if there are clouds. Poor seeing is ok though.
  • Move to a well-observed field, maybe the star-flat field or a supernova field, and begin tracking. We would want to be at zenith angles >30 degrees, maybe more like 45 degrees.
  • All exposures could be 30 seconds in z band.
  • Take one exposure with the dome at the proper azimuth. Record the dome position with the full precision of the new encoders (only nearest-degree positions are saved in the telemetry database).
  • Move the dome somewhere between 5 and 6 degrees in one direction. Take another exposure.
  • Using hand paddle, move dome in steps of about 1 degree (~0.25 m on the dome track) at a time, taking another exposure and recording the dome position at each step.
  • Quit when eyeball or examination of the donuts suggests that half of the primary is blocked by the dome, which will take somewhere between 10 and 20 steps.
  • The shifts of the dome at each step do not have to be very precise, but it is good to record the resultant position as accurately as possible.
  • Finish off by letting TCS move the dome back to an acceptable position, and take one last exposure.

Total time: about 20 minutes. Be aware that the telescope track will be 5 degrees over this time so the "correct" position of the dome will be shifting too.

TCS Guiding Offsets (Rolando)

Check out a new TCS version that correctly accounts for guider corrections when reporting the telescope position.

Install and test accelerometer (Michael Warner, Kevin?)

Pointing Model

Pointing Model Inputs

Do we need to collect more data for the pointing model with the hexapod fixed?
  1. Take a bunch of exposure at zenith in regular mode to setup the hexapod
  2. Lock down the hexapod in x, y, tip and tilt but keep focus under AOS control
    1. Write down the hexapod position and trim values so that we have a record (ICS/Hexapod GUI)
    2. Uncheck Lookup Telescope; uncheck Lookup Filter (ICS/Hexapod GUI)
    3. Switch to AOS 1 mode (init_pid AOS1)
    4. Clear the trims (ICS/Hexapod GUI)

Pointing Model Tests

Test the new pointing model with SISPI compensating for the hexapod position.

From the left over from previous engineering nights

Please delete or edit as needed

  • Calibrate Stars around BD+17 4708 (before 01:30UT): Lower priority for this observing run.
  • Deep Y band observations, fringe tests - This is considered lower priority for this engineering run
  • Regression Script - Low priority