Observing Team

DES Observers: Alex Drlica-Wagner, Andres Plazas
Telops: Alberto Alvarez, Manuel Hernandez, Carlos
Remote Support: Klaus is everywhere
Also Present: Keith Bechtol

Observing Plan

1. Afternoon calibrations (normal set)
2. Weather is predicted to be cloudy first half of the night
3. Evening Standards
4. Run ObsTac
5. Mid-night standards
6. Handover to community observers (04:57 UTC)
7. [Non-DES: Run Bizarro ObzTak (try not to break anything…)]

Conditions

1. Condor seen in the afternoon
2. Sky half covered by clouds at the outset. Some clear area to the west. Clouds generally moving from west to east. Expected to clear by mid-night.
3. DIMM seeing: ~0.6”
4. Wind: (Q1) ~3 mph, (Q2) ~6 mph, (Q3) ~7 mph, (Q4) ~15 mph (gusts of >18 mph)
5. Moon phase: 0.309 (kentools)
6. Seeing: (Q1) 0.9”(r,i,z) (Q2) 0.85” (z), (Q3) 1” (g,r), (Q4) 1” (g,r)
7. Low dome/primary mirror differential temperature are ~2 deg C.
8. Humidity: (Q1) 46%, (Q2) 25%, (Q3) 21%, (Q4) 45%
9. [Quarters of the full night]

Accomplishments

1. Dome flats good (still high on r, VR, and a little on u)
2. 3 standard star fields: SDSSJ0843-0000, SDSSJ0200-0000, C26202/HST (cloudy)
3. 113 wide field survey exposures
4. 2 mid-night standard star fields: SDSSJ0933-0005, SDSSJ1227-0000
5. End of DES Y3: The Year of the Nino

Narrative

1. Applied assessments about 1.5 hours before start of observations.
2. High diffuse clouds appeared to be moving to the east with clear skies several hours to the west
3. Could not get pointing solution on first attempt due to clouds.
4. Increased exposure time to 10s. First offset RA=-3.5, DEC=0.9
5. Standard stars subject to large extinction due to clouds
6. First obstac exposure at 00:42 (516724)
7. PSF is good at the beginning of the night (most exposures have passing Teff)
8. Clouds largely cleared by 02:34 UTC
9. Lots of z-band exposures with pretty good seeing (~0.85”)
10. Last obstac exposure at 04:41 (516836).
11. Handover at 04:55

Quotes of the Day

1. “Take those exposures while you can.”
2. “Don’t kill the messenger, especially when it’s a condor”