Subject: Minutes of Jan. 5 APO User's Committee meeting

From: strauss@astro.Princeton.EDU

Submitted: Wed, 7 Jan 1998 13:15:01 -0500 (EST)

Message number: 237 (previous: 236, next: 238 up: Index)

	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

  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

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

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

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