NGAO topical discussion: Observing Efficiency and Uptime Budgets Telecon Meeting 12/7 D. Le Mignant and E. Johansson 7 Dec. 2006 Attendees; R. Campbell, J. Lyke, E. Gates, M. Perrin

Discussion Outline NG AO background information Our tasks Proposal NG AO SEMP and WBS… Our tasks Observing Efficiency Budget Observing Uptime Budget Current Observing Efficiency and Uptime: words from… Keck Lick? Palomar? Next Generation Definitions for Observing efficiency Observing Uptime WBS Workscope:

WBS 3.1.1.11 & 12 Observing Efficiency: The purpose of this performance budget is to determine what will be required to meet the Observing Efficiency requirement. Also, report on the lessons learned with current LGS AO systems (Keck, Gemini, ESO, etc). A list of all the items contributing to the loss of LGS AO-corrected integration time will be produced along with reasonable allocations of the observing efficiency budget amongst these items. Observing Uptime Budget: The purpose of this performance budget is to determine what will be required to meeting the observing uptime requirement. This budget is only intended to cover the NGAO facility and science instruments (and not the telescope or facility). A list of all the items contributing to downtime will be compiled along with a distribution of the uptime budget amongst these items.

101 nights of Keck II LGS AO ops since Nov. 04 till Jul. 06 Our plans for Keck II LGS in the next couple of years are rather modest.

Keck Overall Efficiency: 101 nights Bad weather impact: ~17% nights dome closed - winter weather ~21% nights impacted by marginal weather Laser faults Lost: 2 full and 5 1/2-nights 9 nights with ~ 1h lost AO faults Minor time lost yet present for 50% of nights Laser Traffic ~ 2% impact Overheads A BIG chunck!

Keck Overall Efficiency: overheads LGS AO checkout 30min/night Telescope slew and pointing Target ID and centering LGS AO readiness 5 - 10 min/target LGS AO optimization 2min per hour on target Telescope/AO handshakes 30+ sec per dither Scientific instrument setup and readout Observing strategy     Ref: 2006 SPIE papers and some Keck internal discussion for K1 LGS AO

Keck Observing Efficiency: Lessons learned Keck NGSAO observing efficiency for nights w/o weather or technical problems at best vary from 25% (snapshot surveys, Lp and Ms obs) to 60-80% for deep-exposure science programs. LGSAO shows roughly the same values, except that it is more impacted by weather and technical problems DLM’s conclusions: For a reliable system in good weather conditions, we are currently mostly limited by Serial (vs parallel) algorithms (DCS /inst/AO) during observations Under-designed telescope pointing and acquisition systems Under-designed AO nodding/dithering hardware and software Under-designed science instrument readout

Review of Keck II LGS AO uptime statistics Major contributors to system downtime: AO Faults Laser Faults Other Faults (instrument + telescope) Space Command (?) Spotters (?) Laser traffic control (?) Should all these categories be considered as downtime?

1. Definitions for Observing Efficiency (what are we talking about?) Currently: Science instrument open shutter time during dark time, including science data and calibrations (sky, telluric, photometric, PSF, astrometry, wavelength) / dark time Does not take into account any metric science-data quality -> very difficult to understand how “observing efficient” an instrument is. A future definition for NGAO? Science instrument open shutter(s) time during dark time delivering science-quality data Each data set is flagged with a science-quality idx Good understanding of the “observing efficiency” for each type of science

2. Definitions for Observing Uptime (what are we talking about?) Currently: AO system and science instrument up and ready to go Does not take into account any instrument performance metric (good calibrations, image quality, operation efficiency, etc) A future definition for NGAO? Science instrument uptime is when it is ready to collect data in support of the science program. Uptime is the opposite of downtime! Downtime includes any time (under adequate weather conditions) not spent on collecting data in support of the science operations.

Observing efficiency work plan Lessons learned Collect experience from other LGS AO systems (Palomar, Gemini, Lick, ESO) and a complex non-AO MOS instrument Summarize, analyze and understand main factors Provide spreadsheet to science and technical team to help build the efficiency budget Look into big terms per science per sub-system Circulate a first phase of requirements Anyone welcome to work on this Need observing experience with other AO/instrument Need experience with high-level software Need new ideas to break limitations of current observing paradigms All need to work fast and efficiently (100 hours total!!)

Observing efficiency budget Built for each science use case Include all observing steps: target acquisition, ID & centering; dithering; science readout and reductions; dithering; command parsing and decision making process; calibrations; etc Should assume a 100% core hardware/software reliability? Why separate Uptime and Obs. Efficiency? Should look into other lost-time statistics (weather, technical, laser traffic) Should look into benefits of: Observing planning GUI and simulation tools Calibration units and auxiliary systems/data during observing (seeing, photometry, air-glow monitoring?) Other possible impact on science-quality data (cirrus, centering stability) System monitoring and recovery to optimize system uptime? etc

Roadmap to an uptime budget Review Keck AO statistics Currently have LGS AO stats Looking for NGS AO stats If not currently summarized, derive from Metrics database Attempt to get uptime statistics from other institutions Remove outliers Failures with large downtimes that can be avoided in NGAO, e.g.: K2 Laser timing board failure with no spares K2 WFC crashes K2 Laser failures may not apply to NGAO laser(s) Use remaining statistics as a starting point for a budget Iterate and fine tune

Conclusions Not all current Keck failures/downtime will map directly to NGAO Primary downtime drivers will be laser and AO system reliability Need to break down AO and Laser faults into finer granularity to draw more and better conclusions