Minutes of APO 3.5m User's Committee Phone Conference July 8, 1996 Attending: Alan Uomoto, Bruce Gillespie, Ed Turner (Chair), Lew Hobbs, Julie Lutz, Michael Strauss (taking minutes), Rene Walterbos Last month's minutes are approved. Agenda: o Refurbishment of DIS in the fourth quarter of 1996. o afternoon and weekend site support--until 3rd Observing Specialist is rehired, need to curtail some weekday and all weekend daytime observing support at site (e.g., afternoon cals and instrument setups, etc.); o secondary o project finances o data archiving at the site--carryover topic from previous meetings; o DIS refurbishment: It has been suggested to take DIS out of service for something like entire 4th quarter, to work on electronics, detectors, optical throughput. Alan Uomoto has agreed supervise or manage this effort to be done by combination of people at JHU and site engineers at APO, with input from the Princeton folk. Alan has manpower available to do this; it would not take effort away from SDSS. Most of the work would actually happen on site (see below). It is not yet clear how to pay for this. Alan points out that most of the work that needs to be done can be done while the instrument stays on the telescope (especially chip problems). The thing it needs to come off for is recoating the optics, which is at least a three-month commitment of time. It remains unclear whether we would get new chips for the camera, as opposed to improving the existing chips. There is also some desire to have another grating to choose from. Alan will write up a detailed plan for the suggested improvements, to be distributed soon. Most users seem happy to have the instrument taken off for improved performance. Don York wants to use DIS over the next year for a program of following up quasars from FUSE, and he is the only person who has explicitly expressed concern about the loss of use of DIS for some period. JHU has plans to build a multi-object spectrograph for APO, but it is still 3 years away, so there is definitely a need to upgrade DIS in the meantime. We decided that there will be no formal limitations on DIS usage in the 4th quarter of 1996. Uomoto et al will work on the instrument during this time in ways that do not require it being off the telescope for lengthy periods of time, and Ed Turner will try to make a schedule which will maximize the periods in which DIS is not being used (around bright time). The refurbishment of the camera optics is the item which would take the instrument out of commission for a lengthy period; this is still a program for the future. Telescope will probably be down for 10 days in ~December for realuminizing of the primary at KPNO (exact dates not yet set). We discussed whether it is possible to get the imaging camera built by Stubbs et al (as a prototype for his wide-field camera in the works) ready for general use in the fourth quarter. This remains to be seen. This camera will have a filter wheel. o Afternoon and weekend site support. We are recruiting a new observing specialist (Dan Long has moved over to SDSS, working days, leaving only two people working nights: Karen Gloria and Eddie Bergeron). An advertisement for a replacement has gone out, applications are starting to come in. With only two people on (Karen and Eddie), afternoon support (for calibrations, remote observing practice, etc.) just becomes more difficult. Observing specialists come on line at 6 PM, it gets dark at 8:30 PM, leaving 2.5 hours to do calibrations. Therefore people are urged not to insist on needing an observing specialist in the afternoons, *especially* on weekends. A new person may be on the job as early as August. o Situation with secondary. Alan: going out for bids on grinding the new secondary (a blank exists!). Plan to take existing secondary out during August shutdown for testing at Steward, but Alan says that it would make more sense financially for this testing to be done by the same people who will make the new secondary. There are rumors from Contraves that different coefficient of expansion of ribs and front plate for Hextex mirrors mean that a perfect secondary at the lab doesn't necessarily mean a perfect secondary in the telescope (if this is really true, this is quite worrisome for the SDSS primary! We definitely need to look into this). We could test this by doing Hartmann tests on the telescope at different temperatures. Shectman's experience at Las Campanas 2.5m shows that tip-tilt guiding (driving the secondary) at 10 Hz has caused dramatic improvements in image quality. Stubbs is in the process of putting in this capability for APO. o Financial constraints: There are a number of costly programs in the works; in addition to the DIS upgrade and the secondary fixes, we have: *Fix primary support to eliminate oscillations there *Replacement of enclosure wheels *Realumination of primary (in December) It is not clear where the funds for all of these will come from. We may thus have financial constraints on the finishing of these various projects. Will probably go to the Board in November to discuss the granting of further funds for next year to do this. We should make sure that our local board members are aware of the needs. So what should we put aside for the moment if we're limited financially? First priority is enclosure wheels; if these fail, we're shut down! (One of the three old wheels is apparently in poor shape, and really needs to be replaced). It remains unclear if the new wheels will not suffer similar problems (Jon Davis should have the answers), and whose responsibility it is to fix them (i.e., manufacturer (L&F) vs. us). o Data archiving Bruce will post some documentation on archiving plans at other observatories, as a basis for discussion. Data are not erased until 7 days after it is taken (official policy is actually 72 hours...), so the problem of data being lost has largely been mitigated. However, we could also think about archiving in order to have data saved for posterity. At the moment, there seems no strong need for this for the immediate future. So let's table this issue for the moment. Bruce and Ed will put together a draft APO policy document to be posted on the APO home page. Gillespie: Thanks to all users to site who are giving the mountain 5 days advance notice. Next meeting: August 12, 12 noon. On the agenda: Plans for posting technical documentation for APO. Bruce will try to get an agenda out the Friday before the meeting. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 73 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