Observing Team

DES Observers: Chris Conselice, Youngsoo Park, Ross Cawthon
Telops: Manuel Hernandez, Alberto Albarez
Remote Support: —-

Observing Plan

1. Standard bias and dome flat sequence
2. Evening standard stars
3. Run ObsTac queue
4. End of the night standard stars
5. End of night calibrations

Conditions

1. Weather in afternoon: 4pm (local): Warmer than yesterday, mostly clear skies.
2. Weather after dinner: 7pm (local): Clear with almost no clouds. Some cirrus appearing in SE closer to sunset.
3. Weather after sunset: 9pm (local): Some cirrus cleared up, some remaining overhead.
4. Weather during night: 1am (local): Continued intermittent light cirrus.
5. Weather summary: 4am (local): Mostly clear night. Beginning of the night with light cirrus, light winds. Towards the end (maybe the last third) we had significantly more clouds and stronger winds. Humidity was constantly around 20-25%.
6. Seeing conditions: Median: 1.19, RMS: 0.29.

Accomplishments

1. Afternoon: Zeros done. Dome flats (ugrizYVR) done. Flats checked. Central dark spot and some local gradients in u. Concentric global gradients in griz, “smudges” on Y. Manuel says it’s normal, and is seldomly noticed.
2. Evening: Standards (SDSSJ000-0000, SDSSJ2300-0000, SDSSJ2140-0000).
3. Survey Exposures 584374-584427; 584432-584631.
4. SN exposures SN-E1; SN-E2; SN-C3.
5. End of night: Standards (SDSSJ0320-0000, MaxVis, SDSSJ0958-0010).
6. Wildlife report: Chris saw a viscacha outside in the middle of the night.

Problems tagged as Synopsis_Problem

No major problems today, no interruption of observing throughout. Some minor problems below.

Minor Problems and Relevant Information

At the start of the night rasicam was briefly offline but was back up shortly. At exposure 584428, sudden seeing spike was observed, where total seeing (~2.4) was twice the DIMM seeing (~1.2). This coincided with the telescope moving from WF to SN, i.e. 584428 was the first SN exposure after multiple WF exposures. The spike quickly died down after 2-3 additional exposures. Exposures 584472-584474 suffered dtsq failures. Y band WF started around 1am, and exhibited systematically larger ellipticities (seeing looked normal). The z band exposures taken together looked fine; not sure whether this is expected. Exposure 584566 and some immediately following (maybe 1~2) suffered dtsq failures.