Subject: solicitation for comments on IR instrumentation possibilities

From: Jon Holtzman

Submitted: Fri, 19 Jan 2001 10:26:07 -0700

Message number: 484 (previous: 483, next: 485 up: Index)

The idea that we need to improve the IR instrumentation at APO has been
discussed at many levels. There are a few possibilities, but the
situation is of course difficult given the diversity of scientific
interests among APO users and the general lack of funds for major
instrumentation initiatives.

One possibility that is being considered is to "upgrade" GRIM; possible
advantages of this are that it may be relatively affordable and also
allow the possibility of low-resolution spectroscopy (as opposed to other
scenarios in which we might get better imagers but lose spectroscopic
capability altogether). Specifically, the idea is to replace the
detector/electronics package in GRIM to provide SIGNIFICANTLY better
readout noise, signal sampling, and stability. In addition, we could also
replace/add grisms to solve the problem of order overlap for spectroscopy
in the J bandpass, and probably provide a more optimal slit width for the
"highest" resolution mode. Given that we most likely cannot upgrade the
detector size (256x256), we would still probably only have relatively low
spectral resolution (to maintain spectral coverage, probably wouldn't
have more than R~=1000, which would still require several slits to get
full coverage in the spectral windows, plus we would have R~=400 to get
full coverage at lower resolution), and we would maintain our current
(small) imaging field of view (2 arcminutes on a side at f/5). Another
possibility might be to provide a cross-dispersed mode for spectroscopy,
perhaps at higher resolution, although I need to further consider the
feasibility of this.

The purpose of this message is to find out how many users would find a
significant scientific benefit if we implemented a scenario like this.
Please comment if you think this upgrade would enable you to do things
which you currently are unable to do. Alternatively, feel free to comment
if there are IR observations you would like to make which CANNOT be
achieved with this proposal, if you are totally satisifed with the
current IR capabilities, any suggestions for other directions you would
find more useful, etc. etc.

Jon Holtzman, NMSU

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