Subject: July 23, 2001, minutes of APO User's Committee meeting

From: strauss@astro.Princeton.EDU

Submitted: Tue, 24 Jul 2001 13:54:48 -0400 (EDT)

Message number: 514 (previous: 513, next: 515 up: Index)

  Apache Point Observatory 3.5m User's Committee Meeting
		July 23, 2001

Attending: Bruce Balick, Rene Walterbos, Mike Shull, Jeff Morgan,
Bruce Gillespie, Ed Turner, Michael Strauss, Lew Hobbs, Alan Uomoto

Not attending: Chris Stubbs, Jon Holtzman

Mike Shull is joining us for the first time as the interim U. Colorado
representative.  The University of Colorado has joined the 3.5m
effective 1 July 2001.  

*************************Status of DIS Camera Upgrade****************
Jeff Morgan:  The dewars have been mechanically built and put
together, and are currently being tested for vacuum; electrical tests
are coming up soon after the electronics are finished (which will
happen soon!).  There are low- and mid-level software routines which
are also being worked on.  When this is done, this will unify somewhat
the SPICAM and DIS software interface (and allow the former to be
operated from Remark). 
  There is still work on venting of excess heat from the instrument,
and the rotator plate, which is in progress/in planning.  We are on
track for installation in early September (there will be at least a
week when the instrument will be completely out of commission).  
  The new improved DIS will have 13.5 micron pixels (very similar to
current instrument), with read noise 3-5 e-, QE > 85% for both chips.
These numbers will be useful for those planning fourth-quarter
observations, when the improved DIS will be available for use.  
  We plan to distribute a brief description of the expected instrument 
performance about the time that the fourth-quarter proposals will be

*****************Status of Telescope Baffling********************
Jeff Morgan:  We still don't have a final report from the
external consulting firm we've contracted with to give us a full
optical model of scattered light of the telescope; we expect it 
this week.  Note that this study concentrates only on the center of
the field of view of the telescope; it covers a region large enough
for the existing instruments, but will *not* be adequate for, e.g.,
Stubbs' planned wide-field imager.  The wider the field of view, the
worse the scattered light is.  This argues that we want to baffle as
far upstream as we can.  
  In any case, they are optimistic about improving the baffling
substantially.  We will be ready to make proposals on actually
building the baffling (figuring out what is most important, most
straightforward, and most feasible) in a few weeks. 

*******************Other hardware news***************************
Jon Davis is working on the detailed design for the new top end.  They
are now looking for an outside vendor to confirm the design and
fabricate it. 

There was great interest in the consortium to make sure that the
near-infrared imager that the U. Colorado people are planning to build
for the telescope (see last month's minutes) be upgradable from the
current 1Kx1K format to 2Kx2K.  This will be tricky, and will probably
involve some additional funding from ARC.  The instrument will have
the option of having an input grism as well, although this will not be
available in the initial version of the instrument.

The summer shutdown starts tonight.  The biggest item is the repair of
the tertiary focus and collimation drives, which causes observed
objects to move and/or jump, especially when switching from one port
to another. 
The other important items include: 
  -Washing the primary and realuminizing the tertiary (which should
improve throughput). 
  -Rebuilding the motors which drive the enclosures.

There is a new base commander at Holloman Air Force Base, with whom
Bruce Gillespie has been in contact.  He's also been in contact with
the base environmental engineer, who has been quite helpful.  There is
also political support within the Alamogordo community for improvement
in the light pollution situation.  They put out more light than does
all of Alamogordo, and it is possible that this can be decreased with
adequate shielding. 

  We have been recruiting a half-time observing specialist for the
3.5m (the other half of this person's time will be working on the NMSU
1 meter).  We've found someone; John Barentine, from Colorado State
University, who will start soon after the shutdown.

  Bruce Balick reports that he, and the U. Washington observers in
particular, have been very impressed and pleased by their work with
the 3.5m observing specialists. 

  The telescope guider has shown a median seeing of 1.2 arcsec over
the second quarter of 2001 (with a minimum of 0.7"), virtually
unchanged from the previous quarter.  That is probably somewhat worse
(0.2"?) than what is seen by the science instruments; that is, we're
getting 1" median seeing on axis.

  The time lost to equipment failure over the last quarter was well
under 1%; the on-sky time was over 60-70% for all institutions, due to
relatively good weather. 

  Rene Walterbos is heading a team to put together a long-term
strategic plan for the 3.5m, and has asked for input from a number of
people.  He has received 10-12 responses thus far.  There is interest
in a Fall meeting to discuss both these long-term plans, as well as
science results from the telescope.  Various of the ARC institutions
are carrying out long-range planning exercises of their own, and 3.5m
planning effort may be of use to them. 

Last month's minutes are approved. 

Next meeting 11:30 AM East Coast Time, Monday, September 10. 

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