Dark Energy Survey » Science Verification

h1. SV Notes for MJD 56234 (starting evening of November 2)

h2. Observers

| *Observer 1* | *Observer 2* | *Run Manager* | *SISPI Expert on Call*| *Eyeball Squad*|

| Soares Santos | Depoy | Soares Santos | Honscheid | Romer |

h2. DECam Configuration and Setup

|SISPI Configuration File|  *sv.ini*|

|DECam constants |*DECAM:CURRENT*|

|Proposal ID| *2012B-0003*|

|Image Processing (Calibration)| *NCSA*|

|Image Processing (First Cut)|*NCSA*|

h2. Almanac

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.

h2. Weather Conditions 

* [[Tololo Weather Links]]

h2. Observing Plan and Goals for the Night

# [[Calibration_Observations|Standard bias and dome flat]] sequence during afternoon

# [[Calibration Observations|Dark frames]] if no bright lights needed in dome.  _Try to get darks today, more important than getting all domes again_

# Please try to get dome open for temperature equilibration at earliest appropriate time, be sure all cooling/ventilation systems are on.

# [[Calibration Observations|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:

# Check on DIMM status, running if at all possible.

# Make sure RASICAM is online if weather conditions permit.

# 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":

# [[Calibration_Observations|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.  

# [[SN_Observing|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.

# *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.

# [[SN_Observing|SN template observations]] in iz for remainder of half-night (will not have time to complete all of them)

# 1:10 AM repeat another [[Calibration_Observations|photometric standards]] sequence of grizY in 3 fields

# 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"

# [[Calibration_Observations|Photometric standards]] in evening twilight

# [[Star_Flat_Observations|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.

# If time permits: [[Polar_Axis|Polar Axis]] determination exposures.

# [[Calibration_Observations|Photometric standards]] at 1:10 AM

If *poor* conditions - thicker clouds and/or seeing >1.4"

# [[Calibration_Observations|Photometric standards]] at evening and 1:10 AM  if thin clouds or clear

# Take [[Star_Flat_Observations|StarFlat sequence]] in i band if thin clouds or clear

# [[Polar_Axis|Polar Axis]] determination

# 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:

# 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.]

h2. 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.

h2. Notes from Observers

h2. Notes on Analyses of Night's Data: