Welcome (Bob Goodrich)
HIRES Detector Upgrade (Grant Hill)
LRIS & DEIMOS Slitmask Milling (Greg Wirth)
NIRC-2 Servicing Mission (Randy Campbell)
VSQ Changes (Bob Goodrich)
Keck User's Group (Bob Goodrich)
Efficient Observing in Semester 2003A (Bob Goodrich & Shui Kwok)
Keck Science Meeting (Bob Goodrich)
Welcome to the new Keck Operations Group Newsletter. The Operations Group consists of the Support Astronomers, Instrument Specialists, and Observing Assistants, who provide the first line of support while you are observing at Keck. The goal of this letter is to share with you significant current or upcoming changes in the operations environment.
Our intent was to set up an unsubscribe/subscribe mechanism, but we have been unable to do that yet. In the meantime, please feel free to send me e-mail if you want to subscribe or unsubscribe, and I will adjust the e-mail list accordingly. We hope you find the following information useful!
The HIRES detector upgrade is proceeding well and is on track for a preship review on November 15, delivery and installation in January, and on-sky commissioning during the first week of February. A recent milestone was passed with the installation and readout of an engineering grade mosaic in the new dewar.
As many are aware, the heart of the upgrade consists of replacing the current antiquated detector with a mosaic of modern devices. The old detector is a 2048 square Tektronix device with 24 micron pixels. The new mosaic consists of three 2048 X 4096 MIT/LL chips with 15 micron pixels butted along their long edges. Two of the chips will be optimized for short wavelength response and the third will be tailored for red response. The figure below shows the dramatic improvement in QE expected from the new detector.
In addition to the improved response, observers can look forward to much faster readout time (of order 30 seconds) and read noise reduced by about a factor of 2. Other anticipated improvements include much better CTE and greatly increased spectral coverage with one instrument setting. The gaps between CCDs will run roughly parallel to orders and be about 60 microns, ensuring minimal loss of coverage.
LRIS slitmasks are currently submitted via FTP to the Keck website two weeks prior to observing runs. Occasionally, observers are unable to meet this deadline, but we have always been able to divert staff from other tasks in order to process late masks. For the first year of DEIMOS operation, all DEIMOS slitmasks have been milled at the Lick Observatory Technical Facility in California and shipped to Hawaii. Starting 2003 October 1, responsibility for milling DEIMOS masks will shift from California to the Keck summit, where our technicians will use a new system that handles both LRIS and DEIMOS
We wish to notify observers of immediate changes to the LRIS slitmask processing system which will affect both the acceptance process and the lead time for slitmask submission. The changes will affect all LRIS observers with runs starting after 2003 October 4.
Changes In Slitmask Acceptance Procedure
The new slitmask processing system will maintain slitmask information in a database, currently residing in California. To submit slitmask files for milling, LRIS observers will use the same web forms that DEIMOS observers have been using for the past year. Submission of LRIS slitmasks via anonymous FTP to Keck will no longer work. To use the LRIS/DEIMOS slitmask submission web form, observers must register and may need to request access for their Internet domain. Please see the following URL for complete details:
The new web interface to the slitmask database offers several advantages over the old FTP system:
You'll be sent email updates on the status of your masks, indicating whether
they've been milled or not.
Changes In Slitmask Submission Deadlines
Previously, it has been CARA policy to request that slitmask files be received at least 14 calendar days prior to observing runs. Enforcement of this guideline has been somewhat lax, and we've often accommodated late slitmasks. This situation is about to change, out of necessity. Whereas LRIS slitmasks typically require only about 15 minutes to mill, DEIMOS masks (which may contain 6 times as many slits) typically take 45 minutes. Special DEIMOS slitmasks designed for narrowband filters may require over 3 hours to mill. Hence, the demand for time on the slitmask mill is expected to increase by about a
factor of 4 once we begin milling DEIMOS slitmasks. The upshot is that it will not be possible for us to mill all slitmasks in time for a run if they are received only days prior to the run. We are thus adopting a new set of rules:
The new slitmask submission system will accept both DEIMOS masks designed with the DSIMULATOR package and LRIS masks created using AUTOSLIT 3.0. By the start of semester 2004A, UCSC will produce a new version of DSIMULATOR for LRIS, allowing observers to design LRIS and DEIMOS masks using the same IRAF-based software package. We appreciate the cooperation of our observers as we enter a brave new world of slitmask milling on the summit.
On the morning of 2003 August 20, the NIRC-2 closed cycle refrigerator cold heads were turned off to allow the dewar to begin its gradual controlled warm up. After 5 days the insides of the cryostat had warmed enough to equilibrate at the ambient temperature while still under vacuum. The scheduled dewar warm-up was in preparation for an instrument service mission to install new narrow-band filters and to investigate some minor mechanical and electrical problems. On Monday, August 25, tools and materials were prepared in the AO room under the leadership of the P.I., Keith Matthews. Keith and other observatory workers donned clean garb to complete the preparations. The K2-AO enclosure had been transformed into a clean room to enable the NIRC-2 service mission and to keep the AO optics and the NIRC-2 dewar as clean as possible. The dewar lid was lifted on Tuesday, August 26 using the hoist mounted specifically for this purpose to the roof of the K2-AO room. The opening progressed smoothly allowing time for several filters to be installed in one of the two wheels that afternoon. The remainder of the filters and blanks were installed in the other wheel the next day leaving time for other jobs and training. The dewar was closed and the vacuum pumping process started later that same day. On August 28, once an adequate vacuum had been reached, the cold heads were powered up to start the cool-down. All tools and materials were removed from the K2-AO clean room and the mission wrapped up. The instrument cooled down over the next several days and the vacuum system was shut down.
The instrument is now fully functional and undergoing tests designed to characterize the new filters. The transmission properties of the new filters will be released in the coming weeks on the NIRC-2 web page as the data are reduced and compiled. We apologize for any inconvenience from the delay in releasing the filter information but we are hesitant to release the specifications and manufacturer's data on these filters because previous expericence with other filters did not meet the specification and/or did not agree with the information sheets provided. The transmission data acquired using NIRC-2 spectra should provide reliable information and we look forward to offering these new narrow-band imaging capabilities to observers.
Those of you passing through Waimea will notice that the room previously used as a library in the VSQ Commons building is undergoing some renovation. In our efforts to provide more functional space for observers—in particular pre- and post-observing groups—we are converting this little-used space into a room where observers can use their own laptops, or Keck-supplied Sun workstations, talk to each other in a relaxed atmosphere, and even have small conferences amongst themselves. The goal is to make the room comfortable enough to encourage more use, and encourage observers to feel more at home.
To achieve this we are removing the bookshelves on two walls, the rather uncomfortable bench seat, and the Windows PC. Instead we will have a built-in counter with a Sun workstation on either end, a pair of switches to connect laptops, a printer, a white board, and some comfortable chairs.
In addition, one of the offices in the Kohala Wing (just down the hall from the Remote Ops rooms) has been designated as a pre-/post-observing office. It will similarly be outfitted with a couple UNIX workstations and a switch to connect laptops. We hope that you will enjoy these facilities, and welcome your feedback. More changes at the Waimea campus are in the works, but let's leave that for another Newsletter!
On August 5, 2003, the first meeting of the new Keck User's Group (KUG) was held via telecon. This group consists of observers from Caltech, UC, NASA, and UH, with a wide variety of scientific interests and expertise. They are meant to represent the entire community of observers to the Observatory, providing a valuable line of feedback for us here in Waimea. The KUG members are:
James Graham (chairperson; UCB)
Andrew Blain (Caltech)
Geoff Blake (Caltech)
Paul Butler (NASA; Carnegie Institution of Washington)
Esther Hu (Univ. of Hawaii)
Shri Kulkarni (Caltech)
Mark Morris (UCLA)
Crystal Martin (UCSB)
Jason Prochaska (UCO/Lick)
Mike Simon (NASA; SUNY Stony Brook)
If you have concerns about observing at Keck, please feel free to contact your KUG representative. Remember, too, the other mechanisms for observing feedback, such as the Post-Observing Comment forms, and feel free to stop by my office and chat if you are passing through Waimea.
The new duty-cycle metrics system allows us to identify nights on which the open-science shutter efficiency is high. To acknowledge the observers with the most efficient programs, we are starting our "Efficiency Hall of Fame," and inducting the first members. These are the observing teams that produced the nights with the highest ratio of science time (time during which the science camera was exposing) to total time available (time between 12° twilights minus any time lost to weather). This is broken down by instrument, so there will be eight "winners" each semester.
The 2003A inductees are:
|Cohen, Agol, Goodrich||
|van Dokkum, Magee, Illingworth, Wuyts||
|A. Cowie, L. Cowie||
|Ghez, Tanner, Morris, Matthews/de Pater, Macintosh||
|Wishnow, Cook, Alves||
Caveats: Of course, there are many factors in determining observing efficiency in this way, and we ignore most of them with this simplistic technique. It is meant simply as a fun way of seeing how well some observers and their programs can do given this simple metric. Also, we do not differentiate the two halves of split nights. You'll note that the NIRC-2 winner was actually two teams (separated by the "/" in the name list) that shared a night. We do not have metrics information on some nights, sometimes because observers delete their raw data files from the sdata disks before the metrics system runs the next morning. Once again, this is meant to be fun, and we hope you all read it in that spirit. And we hope you all feel like winners when you get Keck time, regardless of your actual observing efficiency!
Just a reminder…the Keck Science Meeting is being held at Caltech, on
Saturday, October 25, 2003. Come and see what your Keck colleagues are up to!
See Lynne Hillenbrand's Web site at http://www.astro.caltech.edu/~lah/keck.science.2003,
and e-mail Lynne at email@example.com
if you intend to present a paper.