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W. M. KECK OBSERVATORY

CALIFORNIA ASSOCIATION FOR RESEARCH IN ASTRONOMY

Keck Engineering Time Proposal

Title: / ACS Upgrade On-sky Tests
Date of Observation: / Dec. 10, Jan. 27, 2008
Lead: / Richard Cohen
Other persons involved: / Barbara Schaefer, Sergey Panteleev
Telescope(s) / K2
Instrument(s) / PCS
Sky time Requested / Three increments of 3 to 4 hours of observing time (two of these requested here.). Must be on seperate nights, ideally at least several days apart.
Date(s) to avoid
Required conditions / Reasonable seeing, can be bright sky
Purpose (Please describe succinctly the main purpose of the proposal: development project, general telescope engineering, instrument commissioning, problem trouble shooting, data quality, etc.):
On-sky tests of ACS Upgrade on K2.
Description(Please describe your night-time engineering plan; provide justification for the time request, and include figures, ECR description and other attachments if necessary):
Test those parts of the ACS Upgrade that cannot be tested during the day. Specifically:
  • Software stability under observing conditions.
  • PCS interface under observing conditions.
  • Primary and secondary alignment.
  • UFS measurements of a few segments.
  • System stability (i.e. stack, phase vs. time).
  • Sensor elevation angle dependence and stability.
The final 4 items above will be run with old ACS and new ACS so results can be compared with minimal elapsed time between measurements.
The above tests are approximately described by the following engineering tests:
T922: Realigning telescope optics after segment exchange
T166 : ACS elevation dependence of non focus mode changes
T641: Terrace Mode Stability
T:214 ACS sensor stability"
Justification: The primary mirror is an important part of the telescope. The K2 ACS VME system has been unstable and problematic since K2 commissioning in 1996. Both K1 and K2 computer hardware components are obsolete. ACS software has been frozen for a long time because of the above. These factors combine to create substantial risk for lost observing time due ACS failures.
The ACS Upgrade aims to address the issues above by porting the real-time system to common, modern, off-the-shelf components including highly-configurable terminal servers and very high-performance Intel Xeon-based Sun computers.
Software will be ported from VxWorks, which is esoteric and requires an obscure development environment and cross compilation, to Solaris 10 which is widely used and provides hard real-time capabilities.
This solution is expected to be robust, reliable and maintainable. In addition, the upgrade will set the stage for future improvements to ACS
Plan for data reduction, analysis, and reporting:
PCS and ACS data will be collected in the form of PCS plog, slog and image data files. ACS data will be collected in ACS snapshots. Data will be compared with the usual tools (e.g. UFS data reduction software), manually (e.g. in a spreadsheet) and with purpose-built software.
Tests results will be posted in ACS Upgrade project repository.
Other resources needed:
None.
Status and progress reports from previous use of engineering time:
Status: According to the current project schedule, theK2 upgrade system will be ready for on-sky tests at the beginning of December 2008. Unanticipated delays are possible.
Reports from previous engineering time: Extensive collection of reports from K1 and K2 commissioning are stored in the observatory documentation archives.

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