Subject: 09/11/00 APO 3.5m User's Committee Meeting

From: strauss@astro.Princeton.EDU

Submitted: Mon, 18 Sep 2000 09:13:14 -0400 (EDT)

Message number: 457 (previous: 456, next: 458 up: Index)

  Apache Point Observatory 3.5m User's Committee Meeting
		September 11, 2000

Attending: Bruce Gillespie, Lew Hobbs, Ed Turner,
Michael Strauss, Rene Walterbos, Chris Stubbs, Alan Uomoto

	Results from summer shutdown
	Instrument issues
	staffing update

Jeff Brown has left WSU, and as they have no further astronomers, they
will not be represented in today's phonecon.

***************Accomplishments of summer shutdown********************

Turner: The shutdown concluded essentially on time, and accomplished
essentially all the major tasks planned.  This was perhaps the most
successfully scheduled shutdown yet.  The astigmatism term in the
image quality error budget, which had been the dominant term (in the
0.3-0.5" range), is now down to of order 0.1", negligibly small, due
to improvements in mirror support. We are indeed seeing much better
image quality; recently, a 10-minute science exposure with SPICAM had
0.5" seeing; that's fantastic!

Gillespie and Stubbs: We are now seeing subarcsec seeing consistently
with the telescope.  There is still some work on mirror support which
is on-going.  The telescope ventilation is not what it should be; the
thermal time constant of the primary should be 15 minutes, and was
measured to be 30 minutes many years ago; but now, there is a sense
that it is closer to 3-4 hours (although it is better than it was
before the shutdown).  We're still seeing spherical aberration in the
primary (recognizable now that the much larger astigmatism was taken
out), which appears to be related to thermal derivatives in the
primary mirror.

  In any case, the thermal performance of the primary is much better
than before the work on the vent tubes behind the mirror was carried

  Our confidence in the diagnostics from the Shack-Hartman sensor has
increased considerably; this is turning out to be tremendously useful.

  There are still problems with holding collimation, as well as
windshake; these are of lower amplitude than they used to be. 

  The efficiency of the telescope has also been quite high; users are
quite satisfied with the operational efficiency.  The appendix is an
(unsolicited) recent note from Rene Walterbos about his very positive
impressions after a recent observing run. 

  Stubbs: We've (Peter Doherty and Stubbs) put on a pickoff mirror and
a fast-guider sensor on SPICAM which is the first component needed for
implementing fast guiding. It worked well almost immediately, and has
already been used to gather some engineering data on the power
spectrum of image motion.  It will be a little while before the
feedback loop is put in to use this information to control the
telescope optics to remove the seeing motion. 

**********Instrument issues******************

  The new camera for the slit-viewer upgrade has arrived on the
mountain; it will be incorporated over the next few weeks.

  Lowenstein has been working on an autoguider for the echelle; this
should be available fairly soon. 

  The echelle group will put out documentation very soon on ways to
reduce the echelle data, given apparent problems with reductions and
the order crowding.

  We continue to pursue near-IR Imaging cameras, although there nothing new
to report.  

  Stubbs on the DIS upgrade: the electronics is being fabricated, and
we're working on ways to mount the detectors.  We plan to use EEV
detectors, with very good UV response.  Things are moving!

  We're thinking about mounting Stubb's wide-field imaging camera at

  Gillespie: We had a very successful Fabry-Perot run a few weeks ago.
Remember that it is available to the ARC community, and seems to work
very well.

**********Staffing situation: *******************

Gillespie: We're now down to two observing specialists; Frank Deglman
has left.  Jack Dembicky, chief Mt. Hopkins 2MASS observer, has
been hired.  He will start 1 Dec, but he'll work 20 nights before
then.  Eddie Bergeron has expressed willingness to help for a week or
so.  We're thinking about ways of rearranging responsibilities to
relieve the burden on Camron and Russett in the interim.  In any case,
as the nights get longer, the burden on them will increase, so it is
conceivable that we'll have to shorten nights.

  Given the amount of turn-over, staffing with three people often puts
us in the awkward situation of being down to two observers.  Turner is
exploring ways to avoid these problems. 

  People should consider students of theirs who might be interested in
a career as an observing specialist, and bring the APO opportunity to
their attention. 


  The Board of Governor's meeting is coming up.  We want to gather
together science highlights from the past year.  Thus all user's
committee members should let Ed know of recent substantial 3.5m
results from their department.

  Also, send Rene Walterbos ( lists of publications
based on the 3.5m from your department.

All observers should make contact with the site staff 24 hours in
advance of the run, to confirm instrumental setup and the fact that
they are scheduled to observe.  We've had a number of miscues on
these, and the number has been increasing.  

Remember, the institution is still charged for unused time.  So it
really should be the institution to consider whether disciplinary
action is appropriate.

One possibility is that an automated reminder be sent out by e-mail to
all observers, saying two days in advance.  People are quite
enthusiastic about this idea, and we plan to implement this on an
experimental basis in the first quarter of 2001. 

  The University of Minnesota is looking to take over the WSU time.
They have already explicitly bought the fourth quarter time, and may
join ARC in the future.  

  The Decadal Survey discusses ideas for the National Observing
Systems; whereby US observatories work in concert, and/or try to
reduce redundancies between telescopes (e.g., all the 8-meters have a
similar low-resolution spectrograph; can one be more efficient?).  A
group of people at NOAO is putting together a workshop in Phoenix in
late October to define how this might work in practice.  Ed Turner
will probably not be able to attend.  Different people have very
different ideas of how this might work.

  An obvious telescope that is our sister in this context is WIYN;
they are thinking more strongly about remote observing.  If they have
similar remote observing capabilities, and have complementary
instrumentation, then we could imagine sharing time in some way.

  Last meeting's minutes are approved. 

  Next meeting, 11:30 Eastern time, October 16, 2000

****************Appendix:  Good words from Rene Walterbos************

  The past weekend was the first time in a too long period that I had
the opportunity to observe with the 3.5-m again, for 4 half nights in
a row, onsite. I would like to mention the very positive experience I
had with the telescope, and express my appreciation for all the work
that has been done over the past years by all of you and other
colleagues of us. I think it is fair to say that for the first time I
felt as if I were observing at a national facility (and I mean that in
a positive way...) in terms of the overall efficiency, reliability,
and in many ways also quality of the data. Clearly we have a way to go
in instrumentation, and we should not lose focus on that effort. But
the improvements compared to a few years ago are impressive, and I had
not fully appreciated how effective these have been.  If I can mention
a few: the ease to use SPICAM and the clever implementation to take
twilight flats in a very efficient and quick way, the slitviewer on
DIS which will soon be further improved, the very quick selection and
setup of guide stars, the good image quality at times of good seeing
(one can easily imagine how much further closed loop focus/guiding
would take us), and the overall reliability of the system, in spite
of ongoing concerns about outdated and overly complex computer

I am sure that all of you have been aware of these improvements as
they have occurred over the past years, but they could hardly appear
more impressive than to one who had been too far away from the
telescope for too long.

Rene Walterbos

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