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Proceedings Paper

Design Of A Four-Channel Simultaneous Visual Infrared Photometer
Author(s): Peter R. M. Eisenhardt
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Paper Abstract

A four channel photometer is in the final stages of construction at Steward Observatory. The instrument will obtain redshift estimates for distant (z,l) elliptical galaxies to at least 10% accuracy in short (15-20 minutes) integrations on the Multiple Mirror Telescope (MMT). Redshifts will be determined from comparison of visual and near infrared colors with those expected from a redshifted standard elliptical galaxy spectrum. The four channels are 0.4-0.7 microns (VB), 0.7-0.95 microns (RB), 1.4-1.8 microns (H), and 1.9-2.5 microns (K). Three dichroic filters allow these to be measured simultaneously. A silicon photodiode is used for RB,indium antimonide diodes for H and K, and a photomultiplier for VB. The diodes are all operated at liquid helium temperature to reduce thermal background and preamp noise, while the photomultiplier operates at room temperature using magnetic defocusing. Under these conditions the photometer will have sky background limited performance on the MMT, even in dark time, in all four detectors. Details of the instrument design are presented.

Paper Details

Date Published: 16 November 1982
PDF: 8 pages
Proc. SPIE 0331, Instrumentation in Astronomy IV, (16 November 1982); doi: 10.1117/12.933485
Show Author Affiliations
Peter R. M. Eisenhardt, University of Arizona (United States)


Published in SPIE Proceedings Vol. 0331:
Instrumentation in Astronomy IV
David L. Crawford, Editor(s)

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