Apache Point Observatory 3.5m User's Committee Meeting April 10, 2000 Attending: Jeff Brown, Lew Hobbs, Jon Holtzman, Ed Turner, Michael Strauss, Bruce Gillespie, Chris Stubbs Recent results from and future plans for engineering time Stubbs: The engineering nights have been used to tackle two major issues: (1) Time-varying astigmatism due to something binding up on the primary. (2) Instabilities in the secondary mounting structure is causing image jumping around. On item (2), one of the 3 mount-points (Actuator C) of the secondary is defective; we're going to fix that this week during shutdown; it is not clear whether its the flex pivot or the piezos that's the problem, but we'll get it fixed. [Update: We have found 1, and maybe 2 broken flex pivots; they are being replaced.] The primary mirror problems are adding 0.2-0.3" in quadrature to the seeing; this is not as serious, so it's somewhat lower priority. It also seems to be getting better (although no-one knows quite why). In mid-May, we might use engineering time to track this down. Plans for upgrading DIS Stubbs: (1) We want to replace the slit-viewing camera; Jon Holtzman is taking the lead on this; this should be completed by June. (2) We want to replace the current detectors with modern 2Kx4K detectors (which is what we have in house) (3) We also would like to get improved optics. The design of the current optics says that the images should be quite good. But we haven't seen such good images in practice: is this due to poor alignment, or poor optics? Everyone is very happy with the idea to get the upgraded detectors into the instrument as soon as they are ready. Much enthusiasm all around. Turner: There have been some problems with the way people indicate which of the DIS gratings they want to use. If you're going to use only one, *please* let the observing specialist know this as *early* as possible; changing these things in and out is a labor-intensive activity. Please do not specify a second grating in your observing proposal if you don't need it! An idea: Why not put the third grating in the current slot for imaging mode? A question: how many people actively use imaging mode for DIS? It is useful for those doing multi-object spectroscopy (although no-one is actively doing this now); none of us were aware of any other programs carrying out DIS imaging observations. Holtzman is now ordering the upgraded slit-viewing camera, and hopes to have it in hand by late May. Turner would like schedulers to do sanity checks on the proposals sent in, for such things as the DIS gratings (see above), and inconsistencies on the dates requested. Visitor Instruments: Sean Casey's InSb near-IR camera was on the telescope in the last month. It will still be a long way before it is user-friendly and remotely useable; it requires a number of people on the observing floor to keep it running. There is interest in upgrading it to make it into an integral field spectrograph. This instrument has a field of view of 37" (tiny pixels). Bernie Rauscher says one could buy a MerCadTel array and electronics off the shelf to upgrade GRIM to something competitive: lower-noise and better sensitivity (although still 256x256). It would cost of order $100K. It would not be very difficult to switch this in. In one week, LLNL is bringing an instrument to the mountain: A Fourier Transform spectrometer, working in the optical (but with proper detectors, could be work in IR). It could live at APO for an extended period of time. It fills the same niche as the Goddard Fabry-Perot instrument. We had a brief discussion of which of the two has better performance; there is little conventional wisdom on this, however. Movement is starting to happen on the new topend; it could conceivably happen as early as this summer. Training list of people certified to use the telescope remotely: It has been updated recently based on feedback from the User's Committee. Gillespie and Turner are still considering a policy about how long one stays on this list without a visit to the mountain or observing remotely. Strauss will send e-mail to all those people on list who are not on apo35-general, to find out whether they are still active users. Two free nights are available for Target of Opportunity observations (SDSS and otherwise). Demand for these has not yet been overwhelming. No corrections to last month's meeting minutes. The next User's Committee meeting will be held on May 8 at 11:30 AM East Coast Time. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 428 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