Subject: APO 3.5m User's committee meeting minutes, 5/14/01
From: strauss@astro.Princeton.EDU
Submitted: Thu, 24 May 2001 09:13:21 -0400 (EDT)
Message number: 501
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Apache Point Observatory 3.5m User's Committee Meeting
May 14, 2001
Attending: Bruce Gillespie, Paula Szkody, Ed Turner, Michael Strauss,
Lew Hobbs, Jon Holtzman, Rene Walterbos, Alan Uomoto, Chris Stubbs
************************DIS upgrade*****************************
Stubbs: The detectors and field flatteners have arrived. We're still
on track for a late summer or fall installation. Jeff Morgan has a
design for improved optics for DIS which would result in better image
quality and field scale (0.3" pixels, giving properly sampled images
in both wavelength and spatial scales; this means that one can get
improved imaging, as well as improved resolution with narrower slits,
especially in the blue). This will be modular; the chips can be
upgraded without doing this updated optics at this point (and leaving
the optics change until later, thus not delaying anything).
This optics change would be an update to the Schmidt camera. There
is some confusion about which optical element is responsible for the
UV throughput problem, but it is possible that this upgrade will
improve or possibly even solve this problem.
Alan Uomoto will look into the possibility of getting some narrower
slits, to take advantage of the smaller slit size.
*********Near-Infrared Instruments**********************************
Bruce Woodgate of Goddard has funding from NGST to build a prototype
instrument using microshutter array technology, and he is suggesting
that he bring the instrument to APO for both commissioning and to do
some science. It would be a near-IR imager and spectrograph. It may
include a standard long slit (if the microshutter array stuff doesn't
work). They are interested in rapid follow-up of interesting objects
(such as GRB's); to be useful for this, the instrument would need a
dedicated port (needing a rotator and guider). The detector is an 1K
InSb detector with a 6 arcmin field of view. It would be cooled by
liquid helium, the supplying of which would have some impact on APO
operations.
If U. Colorado joins ARC, they are interested in building an
instrument for the 3.5m. They already have an advanced design for an
infrared camera with a Fabry-Perot instrument (30 km/s resolution).
This would be an 1K HgTe detector (with plate scale TBD), with a large
number of positions on a filter wheel.
A debate ensued about what we should do with two potential near-IR
instruments. Which is better? Which will be a larger impact on
observatory operations? The Colorado instrument has the advantage of
being part of the consortium, with the primary goal to allow the
people in the consortium to do science, as opposed to technology
development (the Woodgate instrument). The Colorado instrument would
have the disadvantage of no spectroscopic capability.
Stubbs points out that the microshutter array technology could be used
as a front-end not just for the near-IR camera, but for DIS.
Certainly, at this point, we want to encourage both these efforts for
the time being. They do overlap somewhat, but both instruments are
either just in the design stage or in the first stages of being built,
and we want to make sure that we get at least one next generation
near-infrared instrument to replace GRIM.
***************************Big Throughput Camera**************************
This is an imager built by Tony Tyson and Gary Bernstein, with four 2K
chips (non-contiguous); 4 times the area of SPICAM. It was used
extensively on the CTIO 4m, but is not on a telescope at the moment.
A guy named Dinesh Loomba from U. New Mexico, a collaborator of
Tyson's, is interested in putting it on our telescope. This is a
temporary measure, until Stubbs' wide-field imager is available. The
BTC looks like it would be pretty straightforward to mount, etc.
For more on this possibility, please see:
http://loki.apo.nmsu.edu/3.5m/btc
The poor baffling of the telescope limits the ability to do accurate
photometry (although completion of the baffling project this year may
improve the wide-field photometry situation substantially); this
drives the question of how useful this instrument will be.
Costs: Some telescope time
Building a mechanical adaptor
Software work to get their software to interface with our telescope
(All pretty minor).
Stubbs' instrument has been held up because of the distraction of the
DIS upgrade. He believes that first light will be sometime next
year.
The user's committee members will poll the community to figure out
what use this instrument might get.
********************Baffling, Summer Shutdown, Etc.*****************
The baffling question: Jeff Morgan is working hard on this, with the
collaboration of an external consulting company. We should soon be
able to interpret the pinhole camera images well enough to start on
the baffling design. There is some pessimism about getting this ready
for installation by the summer shutdown (which was the original plan).
The summer shutdown is currently scheduled July 23-August 31. On
the list of tasks:
-Improvements to telescope throughput.
-Tertiary recoating and primary washing.
-Tightening up tertiary motion.
-Lots of necessary maintenance.
-DIS upgrade (if the timing works out)
The mirror cover automation, and the eyelet automation, are now
complete; this can be done from the control room by the observing
specialists, thereby saving some time, and improving efficiency. One
can't do this via Remark from thousands of miles away, as it brings up
safety issues, but it will make the life of observing specialists
easier (they will not have to run to the dome to open and close the
mirror cover).
********************Echelle*********************
Don York and Bob Lowenstein have put in a series of improvements on the
echelle operation software:
-They've incorporated an improved way of reading biases and
flatfields on the guide camera, which will allow it to go to 16th mag.
So the brightness of targets reachable by the echelle will be limited
not by the guider, but by the echelle itself.
-They have now enabled autoguiding with this instrument; one also
now has the ability to trail bright objects across the slit.
York has made available a quite easy to use echelle reduction
package; contact him directly if you're interested.
********************Observing Specialist**************************
We've had a job ad out for four months to find an observing
specialist who would work for both the ARC 3.5m and the NMSU 1.0
meter; see AAS Job Register #11948:
http://www.aas.org/JobRegister/no11948.html
This position has not yet been filled; please encourage any interested
people to apply.
Last month's minutes are approved.
Next meeting will be held on Monday, June 11, at 11:30 AM EDT
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