To: APO 3.5m Users and Potential Users There is a possible opportunity for access to a low-resolution near-IR spectrograph on the 3.5m, likely in exchange for some observing time for the instrument builders. The purpose of this message is to provide some information about this instrument to determine whether there is significant scientific interest on the part of the 3.5m user community to warrant pursuing this possibility. Initial testing of the instrument could begin early in 2004, and if successful, the instrument could be available for part-time use for an indefinite period of time. CorMASS is the spectrograph originally built by Cornell and U.Mass to work on the Palomar 60-inch telescope. It has been in continuous use for 4 years and is currently in use at the 1.8m VATT (Mt. Graham). It is a low-resolution (R~300), cross-dispersed spectrograph with a NICMOS 3 detector, giving sensitivity from ~0.8 to 2.5 microns. There is a slit, but because the spectra are cross-dispersed, the slit is relatively short. Using the existing instrument on the 3.5m would give a slit of about 6x0.75 arcsec. Overall throughput is around 10 percent but varies across the near-IR. A limiting magnitude for spectroscopic targets of roughly K=15 (10 sigma, 3600 sec) is expected for the 3.5m. The instrument includes a K-band imaging mode used to place objects on the slit. Data acquisition is through a straightforward command line interface. It should be straightforward to incorporate this into the new remote user interface. Recipes for reducing the data in IRAF have been developed by previous instrument users. Much of the scientific work done with this instrument to date has been for identification of cool point sources. More detailed information and some sample images, etc. can be found at the CorMASS home page: http://www.astro.virginia.edu/research/instrumentation/cormass/cormass.html and in an article in PASP 113, 227 (2001): http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001PASP..113..227W For comparison, GRIM has spectroscopic modes of R=200,400, and 800 with corresponding slit widths of 1.4, 0.7, and 0.35 arcsec. It is not cross-dispersed, however, so the entire near-IR cannot be covered in a single exposure. Perhaps even more importantly, the detector in CorMASS is likely to be substantially better than that in GRIM. If you feel that you have scientific interests in, or questions about, using this instrument, please communicate these to Jon Holtzman, holtz@nmsu.edu, (505) 646-8181, and I can accumulate these and pass on expressions of interest to Ed Turner and questions to the instrument builders. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 708 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO