Subject: 04/09/01 minutes, APO 3.5m user's committee meeting
From: strauss@astro.Princeton.EDU
Submitted: Tue, 10 Apr 2001 19:16:12 -0400 (EDT)
Message number: 500
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Apache Point Observatory 3.5m User's Committee Meeting
April 9, 2001
Attending: Bruce Gillespie, Paula Szkody, Ed Turner,
Michael Strauss, Lew Hobbs, Jon Holtzman
Unavailable: Alan Uomoto, Chris Stubbs, and Rene Walterbos
*************RIVMOS IR instrument
Jon Holtzman: This instrument ('The Rapid Infrared and Visible
Multi-Object Spectrograph') is an IR camera and multi-object
spectrograph that Bruce Woodgate of Goddard is building as a prototype
for NGST. The idea is to develop a micro-shutter array in a cooled
focal plane to make multi-slits on the fly. It uses a 1024X1024 InSb
Aladdin, sensitive from 0.6-5 microns. Field of view on the 3.5m
would be 6 arcmin. The design includes both an imaging mode (with 12
filter positions on the filter wheel), and three spectroscopic modes;
R = 50, R = 2000, and R = 5000, the latter two with prism
cross-dispersers. They are looking for telescope time for help in
commissioning this instrument. They hope once it's developed, to
mount it on its own telescope port (with its own guider and rotator,
which presumably we would have to supply), to do fast follow-up of
interesting transient objects, but initially, it would share the port
with SPICAM and DIS (and thus share the rotator and guider). They
hope to get this done within the next year or so. It has the
potential to replace GRIM (although it is not guaranteed that it would
stay here).
Once we pay for the software, the guider, the rotator, and the
cryogen system, this instrument may cost the observatory of order
$250,000, although at this stage, the observatory has not committed to
this yet.
Holtzman and Gillespie are in the process of putting together a
detailed description of the instrument, which will be posted to the
web.
***************Writing CDROMs at the site
Russett McMillan is hearing requests from some observers that data be
written to CD-ROMs at the mountain and mailed to them. Is this
something that we would like to support? It would take 15-20 minutes
of extra work by the observing specialist. Another worry is that
data might get lost in the mail. Also, there is always a possibility
of making some mistake in the copying step. A question to the
observing community: is this a high priority? Is this something that
we would like?
If no strong sentiment is heard from the users, the availability of
this will be announced generally to the users, with the understanding
that it is to be used sparingly and for compelling reasons only
(e.g., problems with the internet connection).
***************Web based proposal form
This would allow certain things to be automated, such as automated
e-mail to people 48 hours before their observing time. It would also
make Ed Turner's scheduling job much easier, if all the relevant
information were formatted in a uniform way. Perhaps we will need a
Phase I-Phase II approach as HST uses: apply for telescope time in the
usual way, and then relevant information for accepted proposals are
entered into the web form. It will of course be useful to the extent
that we have a single form for users at all institutions. APO will
make an attempt at such a form.
*****************Summer shutdown
It will be a shutdown of 4-6 weeks. A number of telescope
house-keeping tasks will be carried out; the only major upgrade is
installing the baffling that Jeff Morgan is designing. Realuminizing
the tertiary, washing the primary, fixing the drive mechanism in the
tertiary, pumping down all the instruments, and so on, are all on the
task list.
So what about the DIS upgrade? The problem is that Jeff Morgan, a
key person on that, will be busy with the baffling, and both things
simply can't be done at the same time. So perhaps we should take the
DIS offline for one dark run (i.e., one month) for the upgrade,
sometime before or after the shutdown.
In the preparation for the DIS upgrade, a small chip was found on
the edge of the Schmidt optics in the blue camera. This probably
happened when the instrument was shipped in 1994. So perhaps we
should replace the relevant piece of optics during the upgrade. The
coating on these optics is at least part of the problem of the lack of
ultraviolet throughput of the instrument. However, there may be other
coatings in the instrument which limit the blue response as well, so
replacing this may not completely solve the problem.
In any case, the detectors/electronics upgrade is the highest priority,
so that's what we'll do, independent of what's done on the optics.
**********Observing statistics, 2001 First Quarter
Remember that the seeing measurements listed in the night logs are
listed only when the refocussing is done, which is not a real
unbiased measurement. Russet and others have been going through old
guider exposures, to measure this in a uniform way. However, the
guider works off-axis, and so gives worse seeing than the on-axis
numbers.
The median seeing of the guider exposures is 1.15-1.25 arcsec, with
the best images in the range of 0.7-0.8". We can probably subtract of
order 0.2" from this to get the on-axis seeing.
In this quarter, 39% of the time has been lost to bad weather.
************University of Colorado
Discussions of them buying WSU's share are advancing. Current
discussion is focussed on what their in-kind contribution might be.
Last month's minutes are approved.
Next meeting will happen on Monday, May 14, at 11:30 AM EDT
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