SV Notes for MJD 56233 (starting evening of November 1)


Observer 1 Observer 2 Run Manager SISPI Expert on Call Eyeball Squad
Soares Santos Depoy Soares Santos Honscheid Romer

DECam Configuration and Setup

SISPI Configuration File sv.ini
Proposal ID 2012B-0003
Image Processing (Calibration) NCSA
Image Processing (First Cut) NCSA


Twilight ends 21:33, middle of night to hand over to community SV at 01:26

Moonrise at 22:37, 90% illuminated, 46 degrees away from our Mini-Survey field on Stripe 82.

Weather Conditions

Clear (Expected)

Observing Plan and Goals for the Night

  1. Standard bias and dome flat sequence during afternoon
  2. Dark frames if no bright lights needed in dome.
  3. Please try to get dome open for temperature equilibration at earliest appropriate time, be sure all cooling/ventilation systems are on.
  4. i-band twilight flats

Operate through night with the baseline Focus&Alignment configuration (Telescope and filter LUTs in use, z Trim on, accumulate). Take note of how large the first focus correction is after slewing to new field: this will determine whether it will be habitually necessary to take a short (~30s) exposure after each slew to allow donuts/AOS to determine new focus position.

Monitor Conditions:
  1. Check on DIMM status, running if at all possible.
  2. Make sure RASICAM is online if weather conditions permit.
  3. A few times per night ask the operator to contact the other telescopes on Tololo to get their seeing value. Record those in the eLog.

If good conditions - sky is clear and seeing is <=1.1":

  1. Photometric standards sequence as soon as dark enough (grizY in 3 fields at different airmasses, preferably one at X < 1.25, one at X = 1.25-1.65 and one at X > 1.65). Follow link for the suggested fields and scripts. Douglas suggests standards can begin 30 min before astronomical twilight.
  2. SN template observations in gr until moon elevates sky brightness (should have time to do 8 shallow fields at ~7 min each, or 2 deep fields at ~30 min each).
  3. SN template observations in iz for remainder of half-night (will not have time to complete all of them)
  4. 1:10 AM repeat another photometric standards sequence of grizY in 3 fields.
  5. Additional grizY exposures in 2 fields for Sky Brightness Measurements
  6. Request of Dara to repeat grizY standards in 2 or 3 fields at AM twilight.
If moderate conditions - thin clouds, and/or poorer seeing <=1.4"
  1. Photometric standards in evening twilight
  2. StarFlat sequences of 20 wide dithers in each grizY (g and r first, with Moon down). Move to lowest accessible Galactic latitude (b>=10 degrees) to increase stellar density w/o crowding. Should take ~20 x (80+30)s = 37 min per filter, ~3 hrs total.
  3. If time permits: Polar Axis determination exposures.
  4. Photometric standards at 1:10 AM
If poor conditions - thicker clouds and/or seeing >1.4"
  1. Photometric standards at evening and 1:10 AM if thin clouds or clear
  2. Take StarFlat sequence in i band if thin clouds or clear
  3. Polar Axis determination
  4. DECal sweeps that were not completed during commissioning
Regardless of cloud conditions, If QR indicates FWHM of PSF is stable at <= 1.1" at any period:
  1. Take 2 focus frames in i band, 25 um steps +- 100 um from donut-recommended best focus position. [This is to determine best focus for science array relative to best focus for F/A CCDs.]

Notes from the 4PM Meeting and Additional Comments

Notes from Oct 31 meeting:
  • We agreed to prepare separate scripts for the red and blue filters for the SN template observations (DONE)
  • Install Steve's new tool (DONE)
  • Get SN finding charts (DONE)
Notes from Nov 1 meeting:
  • Observers should keep a list of bad exposures
  • QR is recovering from a DB problem (Update: FIXED)
  • Added sky brightness test, to be done around 1AM
  • Minor reminders: double check scripts, edit wiki with exp times for DECal, avoid problematic characters in the comments field, make sure the keyword is set to supernova when needed.

Notes from Observers

See Night Summary

Note from GaryB: It appears that SN field E1 was taken more than once and observers thought they were doing E2. Need to check the coordinates in the script.

Notes on Analyses of Night's Data:

Quick Reduce

I'm including some results for last night just to guide observers on some things they can look using Quick Reduce.

QR was running in Automatic mode during the whole night, the DES default configuration and the core 10 CCDs were selected.

It processed 193 of 262 exposures, as it take ~60s to process the 10 CCDs some exposures with very short exposure times were missed (< 15s)

Data transfer of Exposure ID 145365 failed (a click on the RESET button was needed and solved the problem)

The PSF FWHM and Backgorund for as reported by the Observing History tool:

There is a clear anomaly at MJD 56233.268 (Exposure ID: 145508 Filter: z) that must be related with telescope guiding.

The full results are available on this process:

here just one interesting plot for this exposure:

We can reprocess interesting exposures in the morning, for instance I selected the 62 CCDs, turned QR in manual mode, pressed the START button and selected exposures 145409 to 145421 from the mini S82 survey. Here is the straylight plot for Exposure 14541

Difference in sky backgound relative to median CCD (shown surrounded by open green circle) vs CCD

Bluish CCDs have more light relative to the median CCD while redish CCDs have less light.

TASCA (Tololo optical All-Sky Camera) Animated GIF for the night (time stamp in corner of the image is in UT):