Subject: APO 3.5-m Users Committee minutes 2/14/05

From: Bruce Gillespie

Submitted: Fri, 18 Feb 2005 10:14:19 -0700

Message number: 892 (previous: 891, next: 893 up: Index)

                        APO 3.5-m Users Committee Phonecon, 2/14/05

Attending:  Suzanne Hawley, Michael Strauss, Karl Glazebrook, Bruce 
Balick, Bruce Gillespie, Rene Walterbos, Al Harper, Jon Holtzman

Absent: Don York, Russet McMillan, Fred Hearty, John Bally

Minutes taken by Bruce Gillespie


NIC-FPS status:

Since Fred Hearty was in transit to APO and unavailable for this 
teleconference, the NIC-FPS status and plans report was mainly given by 
Suzanne and Bruce G.  Bruce Balick asked about the availability of 
NIC-FPS user documentation.  Bruce G. said that there was a message 
posted to apo35general from John Barentine that points to NIC-FPS 
documentation (see message 851 in the apo35-general archive).  It was 
also pointed out that until all of the user documentation is in place, 
Fred Hearty has offered to help NIC-FPS users personally, both before 
and during their observing runs.  Suzanne added that some of the ARC 
institutions now have one (or more) "seasoned" NIC-FPS users, and that 
new users could try consulting with them.  She also pointed out that we 
have decided to allow NIC-FPS be used as a primary or backup instrument 
outside of the scheduled "campaign" schedule blocks, and that it will 
be treated as a normally scheduled instrument in Q2 (sans etalon).  
Also, Q2 will be the last quarter that GRIM2 is scheduled, so that 
users who need to transition their science programs from GRIM2 to 
NIC-FPS will need to plan according.  There was some discussion of what 
to do with GRIM2 once it's retired.  Since it is ARC property, one 
thought was to surplus the instrument to an ARC institution if anybody 
wanted it.  Al Harper expressed possible interest for UC.

The Fabry-Perot side of NIC-FPS is presently not working well enough 
for science, and will be worked on during the next several weeks.  If 
this is unsuccessful, the F-P will be removed from the instrument and 
is not likely to be reinstalled until after the summer shutdowns. Also, 
the vacuum-hold problem we are presently experiencing with the 
instrument is going to be worked on during the summer, most probably in 


Gamma-Ray Burst programs:

The GRB science document, being assembled by Don Lamb et al., will soon 
be available.  Suzanne will pass it on to the users committee members 
and asked them to study it, share it with interested ARC astronomers, 
and give her feedback.  It was mentioned that the forthcoming document 
should be treated as somewhat proprietary, i.e., don't post it in a 
public place.


Next Futures Committee meeting:

The next Futures Committee meeting will be held in Boulder on 3-4 
March.  At the last meeting in Chicago, discussions included the 
UVirginia Triplespec instrument proposal.  At the upcoming meeting, 
there will be a presentation by Jian Ge on the Florida extra-solar 
planet search proposal, and the committee will discuss the impacts and 
potential interactions between the 2.5-m and 3.5-m telescopes at APO.  
The Futures Committee will need to hear feedback from the community 
regarding this proposal and its potential impacts. Suzanne asked that 
the Users Committee members should talk to the Futures Committee 
members at their respective institutions, in cases where it's not the 
same person.  She also mentioned that she had recently talked to George 
Jacoby about possible future collaboration with WIYN.  Suzanne will 
discuss this with the Futures Committee next month.  Michael added that 
the SDSS project will be at the NSF review of the extension proposal 
later this week.  We are hoping to hear a decision from the NSF before 
1 April.  Rene said it would be useful to know the decision by the time 
of the Futures Committee meeting next month, but that it would be 
unlikely that we would hear anything by then.  On another 
futures-related topic, Suzanne said that she would talk to Karl at the 
meeting about the JHU proposal for potential upgrades to DIS (see 


Telescope & Instruments report:

Bruce G. reported that the telescope and instruments have been working 
fairly well recently, although the weather has been unusually wet and 
cloudy.  Suzanne mentioned that the new top-end CDR is tentatively 
scheduled for April, and that the new spare drive boxes are being 
constructed in Seattle; both are planned for installation this year. 
Bruce G. pointed out that with the uncertainty of SDSS-II, there has 
been (and possibly will be more) staff attrition at the site that 
affects both the 3.5-m and SDSS.  Various contingency plans have, or 
will be, put in place to minimize the consequences of reduced staffing 
levels over the coming months, pending the outcome of the SDSS-II 


DIS upgrade proposal:

Since DIS is our most-used instrument, some CIF funds have been 
budgeted for enhancing its performance.  Jon Holtzman is looking into 
this, and has identified three relatively minor upgrades to improve 

	o new gratings (to improve throughput, and chip and wavelength 

	o UV throughput (fixing the optics to allow throughput below 3900 

	o Dichroic split (to fix a dip in the throughput at the split between 
red and blue)

Jon has asked the Instrument Development Group at JHU to make 
recommendations on how to do these improvements, and it would be good 
if Jon heard comments from DIS users about their grating parameter and 
wavelength preferences.  Also, Suzanne mentioned that the red-fringing 
problem is being investigated, and wondered if anybody had solved it in 
reductions.  Michael said that you need to take flats for every science 
exposure, but others doubted if this is enough.  People with red data 
who either have problems with fringing and/or have solved the fringing 
problem are encouraged to contact their users committee representative 
and Jon Holtzman.  Rene mentioned that doing velocity work in the blue 
is hard, because you need lots of light to get calibration lines, which 
shift as the instrument rotates.  Also, scattered light in the blue 
side has been a problem for some.  Jon said that one idea would be to 
have all three gratings mounted at the same time, with the low-res 
gratings mounted at a fixed angle in place of the imaging mirrors.  He 
wondered if this would be a problem, and most agreed that it wouldn't 
because not many people ever use the imaging mirrors, and they could be 
installed in advance if someone did need to use them.  Also, if all 
three turrets had gratings, doing slit-less spectroscopy would have the 
same caveats.


Other topics:

Rene asked for a summary of the summer shutdown plans.  Suzanne said 
that the plans are not exact yet, but we expect to have a one-week 
shutdown in June to replace the telescope drives, and two-week 
shutdowns in both July and August to do annual maintenance and install 
the new top-end.  All shutdowns are being targeted for bright time.


Last month's minutes were approved without comment. Next phonecon will 
be on Monday, March 28, at 8:30 AM Pacific Standard Time.


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