Subject: APO 3.5-m Users Committee minutes 2/9/04

From: Bruce Gillespie

Submitted: Wed, 11 Feb 2004 10:21:48 -0700

Message number: 740 (previous: 739, next: 750 up: Index)

APO 3.5-m Users Committee Phonecon, 1/12/04

Attending: Ed Turner, Michael Strauss, Bruce Gillespie, John Bally, 
Jim Green, Fred Hearty, Jon Holtzman, Russet McMillan, Bruce Balick, 
Karl Glazebrook

Absent:  Al Harper, Rene Walterbos

Minutes taken by Bruce Gillespie


NIC-FPS Status:

Fred Hearty (the CU grad student who is working on NIC-FPS with Jim 
Green and others) reported on several aspects of assembly and testing 

o Detectors  they are set up to start testing the engineering chip

o Fabry-Perot  the new controller is ordered, expected in late February

o Cables are being constructed

o Filter Wheels  in testing for accuracy and repeatability

o Dewar  Completed 2nd thermal cycle, starting 3rd.  Heat-up and 
cool-down seem well controlled.  Thermal profiles of bench are good, 
with 19+ hours hold-time, which is expected to improve.  Checking bench 
flexure now, and next will begin mounting hardware on bench, and adding 
blankets to dewar.

o Detector testing behind schedule, everything else OK for delivery to 
APO by ~1 August.  Filter wheels are populated, one slot left.  
Baseline filter list will be posted by Fred on NIC-FPS website at


Jeff Morgan's Departure:

Bruce Balick announced that Jeff Morgan, UWash's senior telescope and 
instrumentation engineer, is leaving for a lead position at the 
PanSTARRS project in Hawaii.  Jeff will finish the design of the new 
NA2 baffle for our telescope before leaving.  UWash will recruit a 
replacement, which will take an unknown length of time.  Russ Owen will 
finish with the TUI development this year, and Larry Carey will largely 
take over some the CIF tasks that Jeff had planned to work on.  Bruce B 
said that the APO work is at the top of the UWash priorities this year. 
  There was discussion on the merit of considering other paradigms for 
telescope engineering support at APO--however, this would need to be 
decided at the Director/Board level.



This refers to the Canada-France-Hawaii 12K CCD detector, which is 
being offered "to a good home" because it has been replaced by 
MegaPrime/MegCam, and the proposal by John Bally to use it as part of 
an Integral Field Spectrograph at the ARC 3.5-meter telescope.  A 
summary proposal was distributed the the Users Committee last week, 
intended to evoke discussion and expressions of interest at today's 
telecon.  John Bally said that the CFH12K detector would make a lousy 
imager because the pixel size doesn't well match our telescope, but it 
makes for a superb IFS that would cover ~5 arcminutes, and be capable 
of 10**4 to 10**5 spectra simultaneously, at resolutions ranging from a 
few 100s up to ~10000.  This cannot be easily done with a larger 
telescope, given the normal sizes of lenslet arrays, detector pixels, 
and spectrograph optics. It would provide ARC with a nearly unique 
science niche, namely, the ability to do wide-field integral field 
spectroscope, especially on faint targets (there may be a comparable 
instrument on the William Herschel Telescope).  The design 
considerations are somewhat challenging (e.g., large collimator, large 
gratings).  There are many diverse science drivers and opportunities 
detailed in John's proposal.

Carl G. asked how spectral overlap is dealt with.  John replied that 
the spectra are separated by 10 pixels, and tilted.  Alternatively, for 
high res grating work, narrow pass-band filters prevent overlap, or can 
use a prism or grism to avoid overlapping orders.

This is a very ambitious proposal, more so than for any other ARC 
project since the 3.5-m and SDSS were built.  It would need application 
of outside resources, CIF funds, and possibly the offer of significant 
telescope time.  We could consider a cooperative arrangement with the 
CFH consortium.  What we need quickly is to assess the ARC (and CFH) 
communities potential interest in this proposed instrument.  If the 
user communities seem enthusiastic, we would proceed to negotiate with 
the CFH officials.  We plan to post the proposal to apo35general 
immediately, and users are asked to funnel their comments about the 
attractiveness of the instrument to their respective Users Committee 
representative.  We will also send the proposal to officials at CFHT to 
assess their possible interest in collaborating.

Bruce Balick said that the UWash users were as excited by this proposed 
instrument as any other future 3.5-m instrument.  Carl Glazebrook 
imagines that the JHU users will appreciate and use its unique 
capabilities.  In a separate communication, Rene Walterbos asked that 
we make sure to include the possibility of instead adapting one of the 
SDSS spectrographs for IFS use on the 3.5-m, in the event that the 
2.5-m is closed after the survey.  In answer to a question, John Bally 
said that the CFH12K detectors have 3 to 5 electrons read-noise, and 
one of the "quadrants" has a slightly dissimilar response than the rest 
of the array.

Don York wondered if the IFS would get used much, and remarked that 
there was a proposal for an IFS in the original designs for the 
telescope that had to be cut due to costs and lack of interest.  John 
Bally answered earlier versions of IFSs are generally narrow-field 
instruments, and that this IFS is unique and more powerful because of 
the wide-field format.  He also said that IFS pipeline reduction 
software exists, but would need work before it would be easy to reduce 
IFS data.


TUI institutional contacts:

Ed Turner remarked that he has only received the names and contact 
information for TUI installation from two institutions, NMSU and 
Princeton.  He reminded the Committee that if he doesn't get this 
information shortly from the other institutions, the Users Committee 
member from those institutions will be named the default person for us 
to contact about setting TUI up at your institution.


  CorMASS is coming:

Bruce Gillespie reminded the user community that the low-res NIR 
spectrograph CorMASS is coming to the 3.5-m this spring, provisionally 
for commissioning runs circa 3 - 7 May.  If users are interested in any 
tests or science commissioning experiments during this run, they should 
contact Bruce Gillespie (  More information on 
the capabilities of CorMass will be reposted soon.


10th anniversary celebration:

Users are also reminded that the 10th anniversary celebration for the 
3.5-m is scheduled 27/28 May at APO.  More information will be posted 
shortly.  In particular, Ed Turner is looking for people who would like 
to give a science talk or give poster papers.


New Instrument Call for Proposals:

Ed Turner mentioned that a Call for Proposal for new instrumentation 
projects for the 3.5-m will be issued soon, and be sent to ARC 
institutions and others outside ARC who have worked with us in the past 
or present.  The object of the CP is to select one major new 
instrumentation project that will be ARC- and externally funded over 
the next few years.  The deadline for the CP is likely to be early 
summer, this year.


10Mb/sec connection to APO:

Bruce Gillespie reported that the site is proceeding with the 
acquisition of a 10Mb/sec internet microwave connection, to replace the 
1 Mb/sec T1 phone line connection we have had all these years.  The 
monthly cost of the high-speed connection is roughly double that of the 
T1 line, and there are no up-front capital costs.  We don't know yet 
when this will be in place, but probably sometime over the next few 


Last month's minutes were approved without comment.

Next phonecon will be on Monday, March 8, 2004, at 11:30 AM Eastern Time

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