Apache Point Observatory 3.5m User's Committee Meeting May 10, 1999 Attending: Ed Turner, Jeff Brown, Bruce Gillespie, Chris Stubbs, Rene Walterbos, Ed Kibblewhite, Michael Strauss, Alan Uomoto, Jeff Morgan *******************Anniversaries and Science************************ Today is the 5th anniversary of the official dedication of the 3.5m. Yesterday was the 1st anniversary of the first light for the SDSS. There has been a lot of recent science from the synergy of SDSS and 3.5m. Among the discoveries: a z=5 quasar, a distant carbon star, a series of substellar objects, nearby low-surface brightness galaxies (this latter not connected with the SDSS), etc. Science is happening! The telescope is now producing roughly 1 publication/week. **********Tertiary Rotation Shutdown Report (Stubbs/Morgan)******** Stubbs: The tertiary rotation was motorized, in order to achieve efficient instrument changes. This work happened over the last few weeks. The UW and APO staff worked well together. The overhead in the switching between echelle and an instrument on the other port is now down to essentially zero. The motion is very reproducible, with fields coming back after a rotation to within an arcsec. There is still some tests to be done, but things look good. There is still also some software integration work to be done; once this is done, the operators will have simpler operations to carry out the rotation. Many kudos for Jeff Morgan and those who worked with him for the design and execution. Everyone is very pleased. This was a major to-do of the 3-year plan. The eyelids are not yet automated, but Morgan et al are working on it. This will make life easier for the operators. Brown: Can you take echelle lamps while someone else observes on another instrument? Answer: No, not yet. But Craig Loomis (APO) and Bob Lowenstein (Yerkes) are working on the necessary software upgrades, and this may be implemented in a few months. Note that at the moment, all the instruments other than the echelle use the same port, and so switching between them is no faster now than it was before. To be able to switch between all instruments quickly will require equipping other ports with rotators and guiders. This will not be cheap. During this shutdown, there were a number of upgrades made to the TCC software, and the echelle was recollimated. *************Engineering plans for rest of this year**************** -New secondary Uomoto: We may want to pick up mirror from Steward, even though we don't have the final report from them yet. The final payment will be sent once they send the final report. This would allow us to get an earlier start on getting things ready for the top-end; there are some new fixtures that need to be fabricated, so there are several weeks of configuration work to do. [Late Update:] Jon Davis and Dave Woods are in transit back to APO with the mirror, and the final report from Steward. -Baffling Jeff Morgan and others will be working on this soon. The WIYN example shows that a telescope of this type can be well-baffled, but it is non-trivial. -Summer shutdown Turner: It will start roughly mid-August, and last for one month. Goals include: - Installation of new secondary. - Work on skirt of primary - Altitude drive needs to be rebuilt - Aluminization of primary? Need throughput measurements - Will recollimate the telescope well, after the installation of the secondary, using a new-fangled Shack-Hartman device. (It would be useful to get a baseline by carrying out such an analysis with the existing system.) [Late Update:] The Shack-Hartman device is scheduled for delivery and installation on 20 June 1999. -New top end design/plans Kibblewhite: Preliminary design is in place. The most radical feature is that the top of the top-end structure is open. This allows more room for instrumentation. Ed will be going down to APO to talk to people there next month about specific issues. Idea is to have this built over summer and fall; we need to figure when it would be good to install this. Also, does one simply build a new secondary support unit, or a whole new topend? We know of deficiencies with the current topend, so doing everything over could allow us to ameliorate these problems, perhaps using some ideas from the SDSS telescope topend. Stubbs: This new topend should much improve the mechanical stability of the telescope, and give us new degrees of freedom to help with collimation. A concern: will the topend stay stable when tip-tilt is working? That is, will the whole structure rattle? All this is going to affect image quality. So once secondary is in place, we can figure out what the next dominant term in the seeing budget is. We need more engineering monitoring information on the telescope, to diagnose this. ********************************Instruments************************* -DIS detector upgrade Stubbs and Gunn are eager to work together. Stubbs is planning a trip to Princeton to work with Gunn on this. -Visitor instruments Woodgate has a Fabry-Perot which he is interesting in bringing to APO. There is modest interest in the 3.5m community in using it. Casey has a large-format near-infrared camera. [Late update:] Turner and Gillespie had a telecon with Casey and his team; substantial progress was made on arranging another test run of the instrument on the 3.5m in the fall. Folks at LNLL have a near-IR Fourier Spectrometer They have this instrument, and are thinking of building a larger version for NGST. All of incoming photons are detected, and used. There was a lengthy discussion of the trade-offs involved in getting visitor instruments, where the telescope time comes from, and the imperative not to overburden the site staff. Stubbs: We have a near-term need for IR instruments; we should approach the IR heavyweights: Hawaii, UCLA, Ohio State, Florida for collaborations. Don't forget the AOTF instrument, which has a 1024^2 chip. Could it be made into a more general-purpose instrument? Gillespie is checking with the AOTF team on this. Users report that the echelle is very straightforward to use. It has a very small acquisition field, so be prepared with good finding charts. Given the accurate reproducibility of the tertiary rotator, one possibility would be to use SPICAM as an acquisition camera for the echelle. **************Beyond the Three Year Plan********************* The three-year plan is amazingly on track! Given that funds will be available in the outyears for further development, we need plans for what we want to do over the next three-someodd years. We'll discuss this in more detail next time. Everyone start thinking about this, and talking to your communities about this. Next meeting: 12 noon, Monday, June 21. Previous month's minutes are approved. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 349 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO