Subject: 02/11/02 APO 3.5m User's Committee Meeting Minutes

From: strauss@astro.Princeton.EDU

Submitted: Thu, 14 Feb 2002 09:14:31 -0500 (EST)

Message number: 552 (previous: 551, next: 553 up: Index)

  Apache Point Observatory 3.5m User's Committee Meeting
		February 11, 2002

Attending: Mike Shull, Bruce Gillespie, Ed Turner, Michael Strauss,
Lew Hobbs, Bruce Balick, Jon Holtzman, Rene Walterbos, Chris Stubbs,
Alan Uomoto 

  Status of near-infrared chips
  DIS upgrade
  Plans for using CIF funds
  Long-term planning for the telescope and observatory
  Scheduling the telescope

***Status of Rockwell Chips for NICFPS instrument (near-IR camera): 
  We (Jon Morse) have received more detailed information about the
new-generation detectors that Rockwell is producing; there was some
discussion about these chips in the context of the NICFPS instrument,
and possible upgrades to it.   There had been some discussion of a
chip with sensitivity both in the near-IR and optical; in fact, that
is still very far from production.  But they have a considerably
improved 1024X1024 chip to be used in the first generation of NICFPS,
with improved readnoise and image latency, as well as the ability to
read out sub-rasters.  There is a sense that although this is the
latest and greatest thing, it is reasonably low-risk, in the sense
that it is likely to be quite robust.  There is strong concensus that
we should go ahead with the most modern detectors for this

****Status of DIS upgrade:
  Stubbs: We've had all sorts of troubles, but they are behind us!
Now we have two dewars with pristine chips, readnoise 4.1 e-,
full-well of 150K, and excellent cosmetics and charge transfer
efficiency.  We should ship to the mountain within the next week.  The
cleaning of the red chip worked extremely well.  Rejoicing all around!
The plan is to install it starting Feb 26, and will
disrupt scheduled DIS programs until March 11 (at which point
it will need to be commissioned on the sky).  It will be available on
a shared-risk basis for the DIS programs on March 12-14.  Two concerns:
  -The dewars mate to the Schmidt camera optics in a complicated way;
  -We're meshing the new camera control to the old motor control quite
carefully, but it is possible that it will be more difficult than
  So we're not out of the woods yet!

  It would be nice to have a before and after comparison of the
performance of the instrument (e.g., a standard star for measurement
of throughput); there was some discussion about what might be done.

****Capital Improvement Fund (CIF) spending plan:
  Turner: I am getting close to some sort of convergence on how to
spend the money we set aside for improvements to the telescope and
instruments.  In particular, the programs that are the top candidates
for support include: 
   -The improved detector for NICFPS (i.e., the one discussed above). 
   -The upgrade to the detector and slit guider for the echelle.
   -Upgrade to DIS optics.
   -Work on telescope baffling.
   -Work on new top-end. 
   -The Chicago-JHU near-infrared spectrograph. 
   -On-going projects, such as the new remote observing software and
	     the DIS detector upgrade. 

These are all in different states of negotiation and discussion, and
each program is using different amounts of money and matching grants,

Stubbs: Long ago, we started thinking about a next-generation imager.
The original plan was a wide-field imager, but our thinking is
changing.  Alternatively, let's image simultaneously in a number of
passbands, with multiple dichroics.  This allows one measure colors of
objects, independent of cloud cover.  The field of view will be
similar to SPICAM, perhaps 7 arcmin.  There was some discussion of
having a near-IR channel as well. 
    -Lots of people have been looking forward to wide-field capability.
    -Many dichroics will have a hit on throughput.
    -The filter choice is set once and for all, and is not flexible. 

  Needless to say, the decision about what sort of instrument will be
built has some influence on the CIF plans. 

  Our telescope is f/10, which makes it difficult to build a
wide-field instrument.  If we want to go that route, it was suggested
that we build an instrument for WIYN (focal ratio 6.2), and trade

  At this point, connections with WIYN are informal, but if we wanted
to go ahead with trading time, Ed Turner would contact George Jacoby
(his WIYN counterpart) about setting up a mechanism to do so; we could
start with trading director's discretionary time.

  In replacing the stepper motors on the tertiary, a variety of broken
things were discovered, which took a fair amount of time necessitating
extending the scheduled engineering time (but it was cloudy the entire
time anyway, so no on-sky time was lost).  To avoid tertiary drive
couplings wear and tear in the future, we will only rotate it when at
the zenith, which is a small efficiency hit when switching
instruments.  This is one of the things that the proposed work on the
new secondary and tertiary support system will begin to address.

****Long-term planning exercise: 
    As soon as th2 2002 CIF allocation decision is behind us, Ed
Turner will turn his focus on the long-term plans for the telescope.
There was some discussion about the possibility of getting a committee
to work on this.  These issues are very much tied to the future of
SDSS.  There is a planning activity underway for the future of the
SDSS as well; we want to integrate with that.

****Telescope scheduling policies:
    The current quarter was particularly awkward to schedule, with
many high-priority programs asking for the same time, together with a
mixture of people asking for spread-out time (one half-night every
third night) and others asking for coherent blocks of time, which are
hard to schedule simultaneously. This has led to various suggestions
on how to fix the system, including a suggestion to the institutional
schedulers to rank higher those proposals that have more serious
restrictions on how they are schedulers.  Ed will call a phonecon of the
institutional schedulers in March, perhaps together with the user's
committee, to discuss possible changes in the system.  Note that some
of the schedulers are not active users of the telescope, so people
come from very different perspectives. 

  Last month's meeting minutes are approved. 

  Next meeting: March 11, 2002, 11:30 AM East Coast Time.

APO APO APO APO APO  Apache Point Observatory 3.5m  APO APO APO
APO  This is message 552 in the apo35-general archive. You can find
APO  the archive on
APO  To join/leave the list, send mail to
APO  To post a message, mail it to