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The Ohio State Infra-Red Imager/Spectrometer

OSIRIS is a multi-mode near-infrared imager & spectrometer designed and built by the Ohio State University. It features two cameras to provide narrow- and wide-field imaging modes, and three spectroscopic modes with resolutions of 1400 and 3500. At present it is equipped with a 1024x1024 NICMOS4 HgCdTe array with 18.5 micron pixels supplied by CTIO that permits operation between 0.95 and 2.4 microns.

OSIRIS was built by Ohio State in 1990 with funds from the NSF (AST-9016112) and Ohio State. In its first incarnation, OSIRIS was designed to make optimal use of a 256x256 NICMOS3 HgCdTe array and configured for use at the 1.8-meter Perkins Telescope at the Lowell Observatory in Flagstaff Arizona. The optical design was for wide-field, hence large pixels, with the primary science driver being to enable the Ohio State Bright Galaxy Imaging Survey under the direction of J. Frogel (who also came up with the name). The optics were designed with the idea of being able to eventually accommodate a 512x512 HgCdTe array that was then projected to be available in the "near future".

On his arrival on the Ohio State faculty, Darren DePoy led the effort to incorporate a spectroscopic mode in OSIRIS, which was also funded by a second grant from the NSF (AST-9218449). The full imager/spectrometer was deployed in 199x. With its original NICMOS3 array, OSIRIS received considerable use as a facility instrument at Lowell until Ohio State left the Lowell consortium to join the MDM Consortium in July 1998.

During 199x, OSIRIS spent a year on leave at CTIO, where it saw extensive use on the 1.5-meter and 4-meter telescopes...

The NICMOS3 version of OSIRIS was a remarkably productive instrument...

After Ohio State left Lowell, OSIRIS was effectively left homeless, since it was designed for an f/17 beam, while the MDM telescopes are used at their f/7 foci. In addition, there was already an IR imager/spectrometer, MOSAIC/TIFKAM, in use at MDM, so there was no strong incentive to upgrade it.

But, like its mythological namesake, OSIRIS refused to die. In 1998, CTIO purchased a new 1024x1024 NICMOS4 HgCdTe array for OSIRIS which was installed by Ohio State. The data-taking system was upgraded and some new filters were installed. Starting in Spring 1999, OSIRIS will spend full-time as a facility instrument at CTIO where it may be used by the community on the 1.5-meter and 4-meter telescopes. The formal agreement between Ohio State and CTIO will keep OSIRIS at CTIO for at least three years.

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Updated: 1999 February 16