SV Notes for MJD 56234 (starting evening of November 2)


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 21:34, middle of night to hand over to community SV at 01:26

Moonrise at 23:24, 84% illuminated, 54 degrees away from our Mini-Survey field on Stripe 82.

Weather Conditions

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. Try to get darks today, more important than getting all domes again
  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 - Quit twilights as soon as sky is dark enough for stds

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 for ~2 hrs until moon elevates sky brightness. Given the guiding errors invalidate nearly all of yesterday's SN template observations, we should just start the sequence afresh.
  3. If the 200s exposures are still trailed abandon the SN templates, use time for debugging as needed, and spend sky time taking the Star_Flat_Observations with 50s exposure times to ameliorate trailing.
  4. SN template observations in iz for remainder of half-night (will not have time to complete all of them)
  5. 1:10 AM repeat another photometric standards sequence of grizY in 3 fields
  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

Eyeball squad and SN squad both report that nearly all long exposures are seriously trailed. Trails are diagonal, not aligned to E-W. So top priority for tonight is to insure that guider is on and working properly. The QR report of FWHM's clearly showed worse FWHM on all the long exposures.

Extensive debate ensued about the nature of the problem. GUIDER=3 is set in headers of all the trailed images.

Edited the plan above to reflect that SN templates should not be taken if the guiding issue persists.

Notes from Observers

Here is Night Summary

Quick Reduce

Notes on Analyses of Night's Data:

  • Bunch of E1 exposures, some have good enough guiding to be templates.
  • Useful standards and twilights both AM and PM.
  • 145907-145952 are star flat sequences in i, z, and part of Y.
  • 145999-146010, 146019-035 are 30s r exposures from community time marching around sky in 0.7-degree steps, could be useful for star flats etc.
  • 146075-089 another such sequence.