Nightly Observing Plan for MJD 58461 (starting the evening of Dec 8, 2018)


  • Josh Frieman (Observer 2, Run manager)
  • Rob Morgan (Observer 1)

CTIO Staff


from kentools ephem

mjd 58461, date 20181208, Site CTIO, UT-offset 3 hr
Current local time 16:55 CLST     UT 19:55     SidTim 20:23
Event      Local-Time  Greenwich  Sidereal-Time
Sunset     20:44 CLST  23:44 UT   00:11    3 deg  
Eve. -10   21:24 CLST  00:24 UT   00:52   13 deg  Zeropoint; standards
Eve. -14   21:47 CLST  00:47 UT   01:15   19 deg  Begin obstac
Moonset    21:52 CLST  00:52 UT   01:19   20 deg  
Eve. -18   22:11 CLST  01:11 UT   01:39   25 deg  Last chance standards
Midpoint   01:35 CLST  04:35 UT   05:02   76 deg  
Morn -18   04:59 CLST  07:59 UT   08:26  126 deg  Begin astronomical twilight
Morn -14   05:23 CLST  08:23 UT   08:50  132 deg  End obstac; begin standards
Morn -10   05:46 CLST  08:46 UT   09:13  138 deg  
Sunrise    06:26 CLST  09:26 UT   09:54  148 deg  
Moon position (deg): RA 278.7, Dec -20.8 Phase: 0.111

Weather Conditions

  • At 17:00 clear sky, mild (17 degrees) with a breeze (11 mph), humidity 24%
  • Tonight: Forecast clear skies, Temp. 10 degrees, light breeze shifteing from northwest to south, Humidity ~50%.
  • Detailed hourly forecast | Satellite maps

Observing Plan and Goals for the Night

  • DES Half night
  • Evening standards
    UT Date = '2018/12/09 00:24'     Local time = 21:24
    SDSSJ2140-0000        ra 21:40:00  dec +00:00:00  secz 1.7
    SDSSJ0320-0000        ra 03:20:00  dec +00:00:00  secz 1.4
    SDSSJ0100-0000        ra 01:00:00  dec +00:00:00  secz 1.2
  • Midpoint standards
    UT Date = '2018/12/09 04:35'     Local time = 01:35
    SDSSJ0320-0000        ra 03:20:00  dec +00:00:00  secz 1.3

    h3. Useful links

Nightsum | CTIO Night Report | DECam Logbook
Tololo Environmental Web Page | Detailed hourly forecast | Satellite maps

Notes from 4PM Meeting

Calibrations about to start. Telescope and camera are good.

For tonight:

  • If seeing is bad (Bad means if the psf is > 1.6 arcsec for several exposures in a row with no sign of improvement) complete Photosweep, then Narrowband (details below). If running Narrowband, prioritize E2.

If you have "Bad Seeing" and photometric and not worse than 2.0", do
Photosweep. Instructions can be found here:

Do not bother with this program if clouds are visible on Rasicam or if
seeing is highly variable, for the varying aperture corrections make
it difficult to get to mmag accuracy.

One needs to run a script at CTIO to generate the jsons (see the
instructions wiki page). Having done that the Photosweep scripts can
be found in
with names like: photosweep20180914-2200Z.json

Select the one with timestamp closest to the next top of hour, now in
UT (we got the z added). Do not bother with this is there's < 30
minutes left in the night. A script probably takes an hour.


If "Bad Seeing" and not photometric, or if "Bad Seeing" and everything
else if done, then do Narrowband. Instructions and a description can be found here:

Narrowband scripts are in the same directory as Photosweep, and have names like SN-C3X-N964.json

They are on the SN fields, so select the field that is closest to transit. Transit time for SN fields can be found on this page:

These are expected to be about an hour long. If the clouds are only moderate, we could do these.

Priorities (highest to lowest)

Other Notes