Blanco Telescope and DECam Alistair Walker ACTR meeting 22 March 2013 ver 2

DES Directors Operational Readiness Review April 20-21 Tim Axelrod (U of Arizona & LSST) – Chairperson Fernanda Garcia (Fermilab Accelerator Division) Mario Juric (AURA – LSST) Eric McHugh (Fermilab Particle Physics Div. – ESH) Constance Rockosi (UCSD & Lick Observatory) Larry Stepp (Thirty Meter Telescope) David Wittman (UCSD)

Closeout Presentation - March 21, 2013 B. telescope + instrument + ancillary on-mountain systems with capability to acquire survey-quality data with sufficient efficiency to meet survey science goals Primary Writer: Larry Stepp Contributors: Telescope & Mountain Systems Comments: CTIO is completing a major rebuild of the Blanco Telescope, which added 8 tons of mass and a new Telescope Control System. A number of hardware, software and procedural problems were found during integration and commissioning, but most have been remedied during the 7 months of effort. Findings: CTIO has made good progress rebuilding and recommissioning the Blanco Telescope CTIO has a good system of telemetry to help diagnose problems with the Blanco Improvements have been made in system robustness in response to risk assessment/failure modes analysis 3% telescope downtime during first 260 hours of DECam operation is good reliability under the circumstances Cooperation between the CTIO and DECam teams has been excellent DES Council Review of Operational Readiness for DES Closeout Presentation - March 21, 2013

Closeout Presentation - March 21, 2013 B. telescope + instrument + ancillary on-mountain systems with capability to acquire survey-quality data with sufficient efficiency to meet survey science goals Primary Writer: Larry Stepp Contributors: Telescope & Mountain Systems (2) Findings: Failure to meet inter-exposure time limits is a significant risk to survey efficiency and achievement of the survey area science goals; more improvement is needed The team working on analysis of the BCAM and optical "donut" is making good progress in understanding the flexure and alignment issues, but more work is needed Although not all requirements are currently met, it appears the work is on track to complete the needed improvements to get to acceptable telescope performance by the start of the survey Recommendations Further work is needed to understand telescope flexure and reconcile BCAM and optical "donut" measurements, to improve image quality and pointing performance CTIO should proceed with plans to repair the DIMM before the start of the survey Further improvements in inter-exposure time are needed to ensure science goals can be met DES Council Review of Operational Readiness for DES Closeout Presentation - March 21, 2013

Closeout Presentation - March 21, 2013 B. telescope + instrument + ancillary on-mountain systems with capability to acquire survey-quality data with sufficient efficiency to meet survey science goals Primary Writer: Larry Stepp Contributors: Instrument Findings: DECam performance has generally been excellent There are some issues with CCD linearity, bad column features, etc., but these are being worked Instrument reliability of 1% downtime in first 260 hours of operation is excellent Problems with ghost images and stray light have been analyzed and are being dealt with Maintenance of the detector lab at FNAL to continue learning about CCD properties is an excellent approach Comments: D. Silva reports DECam has already been a very successful facility instrument, with much interest from community observers DES Council Review of Operational Readiness for DES Closeout Presentation - March 21, 2013

Closeout Presentation - March 21, 2013 B. telescope + instrument + ancillary on-mountain systems with capability to acquire survey-quality data with sufficient efficiency to meet survey science goals Primary Writer: Larry Stepp Contributors: Instrument Recommendations It is important to carry through with plans to reduce the risk of exposing the CCDs to excessive light conditions Add monitoring procedures to track any changes in CCD performance with time (fullwell level, etc.) DES Council Review of Operational Readiness for DES Closeout Presentation - March 21, 2013

So, what do we need to do? Technical work is described in the next slides We need to execute two projects (464, 470) We need to strengthen the operations support team The really serious review, run by the DOE + NSF, is April 23-24, at Fermilab

Possible Major Upgrades The installation of an air handling unit (or units) in the dome plus installation of a new set of 2.5 inch pipes from the outside-dome chiller is presently being estimated. Cost is likely to be of the order of $50K. It is likely that funds will only become available in FY14, that is a discussion that will take place when we know the costs (end of March). (464) The replacement of the Blanco primary axial support transducers (33) is about to be estimated. Assuming we do this project, it is likely to be both quite expensive and manpower-intensive, and require telescope down time, thus it’s difficult to contemplate doing this before the 2014A semester. (470)

March Replace Tachometer Oil Seal (Patricio) Telescope open-loop tracking adjustment (German, Michael) Efficiency – test shortening the “TCS Delay” (Alistair) Guider tests, need clouds (Alistair) Skymap to build a primary mirror support LUT (Alistair) Exposure to exposure efficiency tests (Alistair) Check dome positioning (Alistair, Omar) Decide whether to make default AOS-5 instead of AOS-1 (Alistair) Test suite of observations (Alistair)

April Oil scrapers? (Freddy) Install PF cage covers (Freddy) Install mask on the g filter (Patricio) Another set of all-sky measurements with the laser system + bigger CCD camera, and Bcams (Roberto, Freddy, Tim) Test suite of observations (Tim)

May Hydraulic oil cooler (Esteban, Edison) Sequence code changes? (Juan Estrada) Install better pointing model (if not before, German, Rolo) Test suite of observations (Alistair)

June Test suite of observations (Alistair) F/8 work (Tim et al.)

July Warm up DECam (Telops, Alistair) Install replacement LN2 pump (Herman Cease, Freddy, Telops) Fix leaks, general maintenance of LN2 system (ditto) Install masks on the other 5 filters (Patricio, +?) Disable remaining fan sensor, replace two fans (Terri Shaw, Lee Groves, Telops) Rewire remote crate switch, check grounding (Steve Chappa, Telops)

On-going activities, plus work not assigned to a particular time slot yet Tune the daytime mirror cooler algorithm (Alistair, Edison) Install remaining temperature sensors (Edison) Plumb second NESLAB (Telops) Plumb second roughing pump in Cass cage (Telops) Plumb second air compressor (Telops) Telemetry for LN2 hoses vacuum jackets (Marco) External photodiode bright-light sensors (Marco) Backup generator for pumps (Marco) Install accelerometer on PF cage (Michael)