Subject: 12/09/02 APO 3.5m User's Committee Meeting Minutes
From: strauss@astro.Princeton.EDU
Submitted: Tue, 10 Dec 2002 13:18:15 -0500 (EST)
Message number: 636
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Apache Point Observatory 3.5m User's Committee Meeting
December 9, 2002
Attending: Al Harper, Bruce Gillespie, Ed Turner, Michael Strauss,
Rene Walterbos, Bruce Balick, Alan Uomoto, Jon
Holtzman, Jon Morse, Don York
Absent: Chris Stubbs
Agenda:
-Telescope Azimuth drive failure and repair
-Results of the 11/26 Board of Governor's meeting
-Plans for the ARC community meetings at the Seattle AAS
**************Telescope Azimuth Drive**************
As you probably have all heard, the telescope azimuth drives failed
on us the weekend before last. They are close to being repaired. The
cause of the failure is not clear. We use speed-reduction devices
that reduce the drive motors' capstan speed by a factor of 100; these
have preloads of 100-1000's of pounds. We've had troubles with these
throughout; they are a maintenance nightmare, and each of the three
drives (one on altitude, two on azimuth) has needed complete
rebuilding every 2-3 years. This system is not in common use on
modern telescopes. The failure could be caused if the telescope were
to bump into something, such as the building (which indeed happens
from time to time). In the process of this repair, we've just added
limit switches between the telescope and building to try to prevent
such collisions.
We hope to get the telescope reassembled Monday/Tuesday, and on the
sky Tuesday evening. Science observing could begin on the second half
of Tuesday night, more likely Wednesday.
We own a pair of direct-drive motors like the ones used in the SDSS
telescope, which do not have speed-reducing mechanisms. These were
built as engineering prototypes for SDSS and were briefly but
unsuccessfully tried out on the 3.5-m telescope many years ago. We
have been experimenting with these motors on the bench this past year,
and they could conceivably be put in the telescope and made to work,
since their bugs have already been worked out by the SDSS project.
*****************Report to Board of Governors**************************
Bruce Gillespie and Ed Turner presented their report at the BoG
meeting on November 26. It included the usual routine reports of
numbers of nights assigned to different institutions, fraction of time
lost to weather, and so on. We had <2% of unscheduled downtime over the
last year. It will be worse this next year, given the problems with
the drives just discussed.
The overall 2003 forecast, budget was up 2.1% over previous year,
for a total of $1.294 million, which includes general site operations,
"sinking fund" augmentation, capital improvement projects, ARC
corporate expenses, and a small amount of income.
The science highlights covered, among other things, a project led by
Don York (and involving collaborators from Chicago, Hopkins, and
Colorado), an echelle survey of highly reddened OB stars. FUSE was
launched a few years ago; it observed 40 stars to look for molecular
hydrogen absorption in reddened directions. The idea is to look for
diffuse interstellar bands, and correlate those with the molecular
hydrogen. It was found that the strong bands are associated only with
atomic hydrogen. They also found a series of weaker bands correlated
with C_2. 5-6 papers are in the works; this was based on 80 nights of
observing over 3.5 years. This was doable both because of the large
amounts of time on a large telescope, and because of the quality of
the echelle.
The imaging performance of the telescope is indistinguishable from
the previous year: a median seeing of 1.18", with average deviation of
0.46". The best seeing is about 0.6-0.7" (all as measured off the
guider, and is therefore a bit off-axis).
We have understood that the major contribution of the telescope to
the seeing is the decollimation effect, discussed in detail in
previous user committee meetings. To really tie this down may require
undertaking the new topend project.
One possibility is to give the users the option of spending 1/2
hour of their time for redoing the collimation with a Shack-Hartman
test, for those who need the absolute best image quality.
The breakdown of usage of the instruments is as follows:
44% DIS
12% GRIM
20% SPIcam
15% Echelle
9% Visitor instruments (mostly Fabry-Perot)
Note that the Goddard Fabry-Perot is open for use for the APO
community. Don York reported that he has used the instrument
remotely, but there is a fairly steep learning curve. He plans to
distribute soon notes on the instrument and its usage.
Stubbs et al are working on a lunar laser ranging experiment. They
will be observing both during day and night, using small bits of time
throughout the month to follow the Moon's orbit.
Plans for 2003: We did not submit to the board a definite Capital
Improvements Fund (CIF) plan for this term: there is uncertainty on which
instrument projects are going forward, driven in part with
uncertainties about which of the pending NSF proposals will go
forward.
Among the items that might be included in the CIF are:
-The planned JHU/Chicago Near-IR Spectrograph
-NIC-FPS
-Upgrade to the Echelle detector
-A simultaneous multi-color imager a la Stubbs
-A new topend
-Upgrading DIS optics to increase sensitivity in the UV
-A variety of telescope engineering projects, including the baffling
and software upgrades (both of which in fact are on-going.
We could afford to fund 2-3 of these over the next year; hard
decisions! This is an important topic for the AAS meeting discussion
(see below).
There were a set of strategic issues also discussed at the meeting:
-Will the 3.5m remain a general purpose telescope, or a specialized
niche telescope? York argued strongly that we lose our
uniqueness and niche if we simply try to be a general-purpose
telescope facility in the KPNO mold. To what extent are there
large coherent scientific programs in mind for the next
generation of APO instruments (including NIC-FPS and the
near-IR spectrograph)?
-How can we leverage CIF funds to get more instruments (matching
funds, etc.)? The only way that has worked thus far seems to
be via selling telescope time.
-How we would deal with the 3.5m budget if SDSS shuts down? A rough
estimate is that this would increase 3.5m operating costs by of
order $200-300K, of the same order as the CIF budget.
-Discussion of human resources limitations, that limit our ability
to get projects done (often parallel projects we want to do
both require the full-time attention of the same people).
-Ed Turner has been director of the observatory for 7 years. He is
considering stepping down at the end of his third three-year
term. Thus one year from now, the board will want to start
searching for a new director.
There will be a formal announcement about this, but we hope to meet
one or more times at the Seattle AAS meeting, to discuss the above
questions, and to set priorities in the CIF. Among the possible
times are:
Monday (January 6) 11:30-2
Monday, Tuesday, Wednesday evenings (5-7 PM)
A final piece of news: the DIS optics upgrade will start at the end
of this week.
Last month's meeting minutes are approved (although note that the
date at the top of those minutes are incorrect!).
Next meeting on Monday, January 13 at 11:30 AM East Coast Time.
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