Apache Point Observatory 3.5m User's Committee Meeting ****************January 5, 1998********************** Attending: Chris Stubbs, Michael Strauss, Bruce Gillespie, Kurt Anderson (for Walterbos), Alan Uomoto, Ed Turner, Jeff Secker, Ed Kibblewhite Agenda: Who gets charged for open time? Policy for Director's Discretionary time. Good news on seeing Snow policy Status of Secondary negotiations Status of DIS Open Time Walterbos brings up the following issue: some institutions, notably Princeton, are chronically undersubscribed. As the ARC policy is to make the institutional shares balance out on a 3-year timescale, does this mean that Princeton is accumulating lots of time it can ask for later? This does not seem fair to all and sundry. Undersubscription results in open nights; who should get charged for that? It is people's understanding that the ARC policy is to even out the vagaries of scheduling (which means that Turner need not meet the institutional allotments exactly every quarter), and it is not for the case for not asking for time now, so as to be able to use it later, when the telescope is working better. Therefore, we should not indulge an institution which chronically is undersubscribed. Turner will circulate a straw-man solution to the problem (after getting Rene involved, who brought it up), and present it to the board. What should be done with Director's Discretionary time? It can be use to smooth out scheduling anomalies due to the various ways in which people get screwed in the scheduling, or some egregious screwup on the observatory's side. Also, it can be used to reward instrument builders. But there is a building consensus that the time should primarily be used for projects involving excellent science; DD time is really ideal for projects which can't be done with the telescope time fragmented between institutions the way it is, like, for example, gamma-ray burst optical followup. "Key Projects" A lot of support for doing more than individual projects, "A poor man's KPNO". Ed will put out a call for proposals for this kind of thing. Who should decide on these things? Use the User's Committee as a "superTAC"? Should the director simply use his own discretion? The consensus that it should be the latter; the director should call upon expertise when needed. WSMR time acts like rain on the schedule, but the director has the option of reimbursing people with DD time. Good news on seeing Gillespie asked Gloria to look at image-quality statistics with time. The seeing has dropped by 0.4" over the past year (wow!). The logs indicate that since the August shutdown, the number of nights of 1" or better seeing seems to have really gone up. Largely due to improved collimation of the telescope? Snow policy 3 usable nights in the last month or so were lost to snow/ice on the roof of the dome. Heaters are the same as what they use on MMT (but they rarely get snow there). So heaters are quite inadequate. Over Christmas, a combination of heavy snow and very cold conditions meant there was a lot of build-up, including heavy ice. Our policy is not to send people to the roof to shovel; it is just too dangerous. Over Christmas, this policy was broken for an experiment. Another possibility: aircraft de-icer (basically anti-freeze); it is not obvious whether this is environmentally benign. Also thinking about improved heaters. Status of Secondary negotiations Uomoto: Secondary negotiations are in decent shape. Sometime this week, the contracts with both Swales (who are doing the polishing cell) and Steward will probably be finalized. Steward: it will take as little as 8, and as much as 18 months to deliver mirror after first receiving it. Status of DIS There is a possibility of getting Advanced Camera chips for DIS, with work between JHU and UW to get electronics, dewar in place. Plans for all this are in the works. Jim Crocker is getting involved with this as well. Lucinio claims that he can make some real improvements in the read noise of the existing chips, in collaboration with Jim Gunn. It may be just a day of work of the two of them together. Uomoto: The two new medium-resolution DIS gratings are in hand, and are ready to go in. Remember that these will *replace* the low-dispersion gratings, although these can be put back in if necessary (especially after the UV throughput problem is fixed). With the medium-dispersion grating, we can cover 3850-8150 A at 3 A/pixel dispersion on the blue side, 3.5A/pixel on the red, in one swoop. Here are more details from Alan: New medium dispersion gratings for DIS have arrived and will be tested in the next few months. Here's a summary of what will be available (these are approximate numbers only): Low resolution Blue Red Dispersion 6.2 A/pix 7.0 A/pix Wave range 3175 A 5600 A Medium resolution (new) Blue Red Dispersion 3.1 A/pix 3.5 A/pix Wave range 1590 A 2800 A High resolution Blue Red Dispersion 1.6 A/pix 1.1 A/pix Wave range 820 A 880 A The crossover wavelength is 5350 A. Note that the addition of the medium dispersion gratings is an enhancement, not a replacement, of current functions (some people have the incorrect impression that the low dispersion mode will not be available). While DIS handles only two pairs of gratings at once, it should be possible to specify the setup needed at the beginning of the night and have the proper gratings installed. Grating changeouts during the night are not a good idea, though, so scheduling will need to account for program requirements. Previous month's minutes are approved. Next meeting, February 9, 1998, 12:30 PM APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 237 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