Subject: Minutes of 01/10/00 meeting, APO User's Committee

From: strauss@astro.Princeton.EDU

Submitted: Mon, 10 Jan 2000 14:25:45 -0500 (EST)

Message number: 411 (previous: 410, next: 412 up: Index)

  Apache Point Observatory 3.5m User's Committee Meeting
		January 10, 2000

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

  Status of telescope now that science operations have started again.
  Status of GSFC IR camera
  Efficiency of operations; use of afternoon time.
  DIS upgrade.
  Certified Observers

***************Status of Telescope**********************************
Turner:  We are back in operation, as of one week before Christmas.  I
was surprised and pleased at how gracefully the operations got "back
on their feet"; lots of things that hadn't been exercised in many
months worked well. 
  The image quality has been as good as 0.5" in the near-IR with the
new secondary, which is excellent.  However, there seem to be
wind-shake problems which are dominating the seeing budget in many
cases.  In installing the new secondary, it seems that we've given up
some of the rigidity that kept that problem under control (see the
following paragraph for other thoughts on what this may be due to). 
  We have not yet done a full careful recollimation of the telescope
via the Shack-Hartman device.  So it is possible that some possible
astigmatism, which has been reported by Chris Stubbs, is due to this
(it is also possible that what Chris was seeing was due to wind shake). 
A few days ago, Shack-Hartman data were gathered, and are being
analyzed now. 
  A lesson: the new topend will definitively have to worry about
wind-shake in its design. 
  All indications are that the secondary optical quality are as good
as design specs. 

Gillespie: There also seem to be tracking/telescope stability
problems.  These may not just be windshake, but may be some problems
with the drive servo tunings, or with the primary mirror support
tuning.  We're all looking into these problems as we speak.  We
expect/hope that in a month or so, the collimation and windshake
problems will be under control.
****************Status of GSFC Infrared Camera******************
GSFC IR camera will be observing on the telescope for three-night runs in
both February and March (the latter by Ed Turner and collaborators).  However,
there seems to be some uncertainty on the GFSC side associated with
the fact that Sean Casey has left GSFC.  Also, the instrument is
*quite* far from being a remotely operable facility instrument.  We
are hoping to work closely with the people who built the instrument in
order to upgrade their system to make it more user-friendly.  They
also want to do further work on it using other telescopes later this
calendar year.  So it is not as clear the extent to which it can
simply stay in APO.  We're talking to them, but we're not sure how it
is going to play out.

A question to the user's community: how useful would it be to have a
camera which you have to travel out to the site to use?

Note that Bruce Woodgate, who is involved in this camera, is observing
on our telescope for a number of nights with his Fabry-Perot
instrument near the end of March (both DD time and collaborations with
APO community members).

************Observing Efficiency and Afternoon Preparations************
Walterbos: Who has access to the telescope in the afternoon?
Astronomers who spend the afternoon thinking about their observing
program, carrying out calibrations, etc., are properly warmed up and
revved up for observing efficiently as soon as it gets dark.

Gillespie: A lot of this happens already, at least in an informal way.
There is an observing specialist at the telescope three hours before
sunset.  There is a preflight checkout of the telescope, which takes
45 minutes, late every day.  In any case, all such efforts can be
accomodated, if the mountain staff gets sufficient prior notice (at
least 24 hours in advance). 
  But it is a real problem; people often start the night not having
thought their observing through clearly enough, and therefore are not
very efficient at the beginning of the night.  This is one of the
disadvantages of remote observing; when you travel to the observatory,
you are naturally thinking about and preparing for your observing
program all afternoon.  We need to make clear to the observing
community the importance of getting yourself into an "observing frame
of mind" in the afternoon before your first night. 

*****************Status of DIS upgrade*****************

Strauss: A 1/2 hour exposure of a i'=20.5 (AB) SDSS quasar candidate
with DIS (low-resolution) yielded a definitive redshift (z=3.8).  Not
bad for a 3.5m telescope!  The spectrum was not high-quality, but
unambiguously yielded Ly alpha line.

Stubbs: We are pushing to get the detectors on DIS upgraded, and work on
upgrading dewars to cryotigers.  Work on the optics will not happen at
this point.  The limitations are Jeff Morgan's time, and he is also
working on baffling, and also analyzing the optical quality with the
new secondary.

Through colleagues in Rio de Janeiro, Walterbos knows a Brazilian
fellow who might be able to come to work on various aspects of the
CCDs and possibly the optics.

*******************What it means to be a certified observer*********

Gillespie: The list of people who are formally certified to be remote
observers exists off the APO web site
(  We should remove those
people who are no longer active users of the telescope, and/or who
haven't been to the telescope or observed for many years.  Indeed, we
need to think the whole issue through about how people are certified;
Bruce and Ed will think through how to work on this, and post a
recommendation.  Does one's certification have a statute of
limitations on it?  But remember that it is primarily an
*institutional* responsibility to make sure the their time is used in
the most efficient way, by confirming that their observers are
familiar enough with the system that they can use the facilities

  Previous month's minutes are approved. 

  The next meeting will be held on February 7 at 11:30 AM East Coast

APO APO APO APO APO  Apache Point Observatory 3.5m  APO APO APO
APO  This is message 411 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