Instrument Status

• General: DEIMOS has survived its adolescence and is now functioning as a lean, mean, redshift-measuring machine! Reliability has been very good over the last 6 months.
• Slitmasks: The new guide installed in July 2003 has succeeded in fixing the longstanding problem with buckling slitmasks. Rarely have we seen any problem with mask buckling since last summer.
• Gratings: All grating stages are functioning reliably.
• Filters: Filter weights remain unequal and thus the filter wheel is unbalanced in certain configurations. A software fix has allowed the instrument to be used when the wheel is slightly off position, but we would still like to equalize the weights. Lick is willing to do the work, but is worried about damaging the filterts in shipment.
• CCD systems: Both the detector arrays (FCS and science) and associated electronics continue to perform well. We had a serious problem recovering the FCS crate after the power outage. This was traced to a longstanding problem with the configuration of the DEIMOS host computer, preventing the crate from booting up. Amazingly, this apparently marked the first time the crate had been rebooted in nearly two full years of operation!
• Support: Jim Lyke has completed training in DEIMOS support and is now responsible for a significant fraction of the nights.
• Optics:

Slitmask Processing

• New system: a new system (computer and software) for milling DEIMOS and LRIS slitmasks has been commissioned at the summit, replacing the old SURFCAM system. Two significant implications:
  • all slitmasks are now milled at the summit, allowing us to process late slitmask submissions
  • LRIS observers now converted to using the web-based submission system at Lick to submit slitmasks
• New procedures:
  • Single operator. Chris Hunt is now the primary slitmask mill operator at the summit. About 40% of his time is allocated to the task, meaning that masks are generally being milled only 2 days per week (usually Monday and Tuesday). We hope that having one person responsible for milling operations will streamline operations and produce more consistent mask quality.
  • Ultrasonic cleaner. Chuck Steidel generously funded the purchase of a new ultrasonic cleaner for DEIMOS and LRIS masks to remove grit from the slits prior to insertion in the instrument. This should yield cleaner slits and improve background subtraction. The cleaner has been delivered but it awaiting commissioning.
• New policies:
  • Increased lead time. Since September 2003, observers are now requested to submit masks at least 28 days prior to their run. Median submission lead time over the last 6 months has been about 23 days, and only 30% have been received by the deadline.
  • Procrastinator tax. Plans are afoot to institute slitmask milling fees to recoup the cost of producing masks. DEIMOS masks cost Keck about $100 apiece to mill, LRIS somewhat cheaper. Mask fees may be based on lead time, effectively levying a fine on observers who submit masks late.

On-Sky Efficiency

Top 10 Task List

1. [Dahl/Wirth] Fix SKY rotator time-to-limit algorithm
2. [Wirth] Modify startup scripts/pulldown menus to support remote eavesdropping
3. [Wirth] Write user manual
4. [Wirth] Update troubleshooting pages
5. [Mason/Lewis] Install ultrasonic cleaner for DEIMOS/LRIS masks
6. [Mason/Wirth] Coordinate transition of slitmask milling to Hawaii
7. [Wirth] Document slitmask milling procedure
8. [Mason/Wirth] Review preventive maintenance plan
9. [Wirth] Adapt Arcplots widget for DEIMOS
10. [Wirth] Coordinate DEIMOS configuration database effort

Recently Completed Tasks

• [Wirth] Provide convenient focus acquisition/analysis software
• [Wirth] Train summit staff in DEIMOS reconfiguration procedures