7.1 FORCAST Instrument Overview

The Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST) is a dual-channel mid-infrared camera and spectrograph sensitive from 5 - 40 μm. Each channel consists of a 256x256 pixel array that yields a 3.4'x3.2' instantaneous field-of-view with 0.768'' pixels, after distortion correction. The Short Wave Camera (SWC) uses a Si:As blocked-impurity band (BIB) array optimized for λ < 25 μm, while the Long Wave Camera's (LWC) Si:Sb BIB array is optmized for λ > 25 μm. Observations can be made through either of the two channels individually or, by use of a dichroic mirror, with both channels simultaneously across most of the range. Spectroscopy is also possible using a suite of six grisms, which provide coverage from 5 - 40 μm with a low spectral resolution of R = λ/Δλ ~ 200. The instrument has space for cross dispersing grisms allowing for high resolution cross-dispersed (XD) spectroscopy at R ~ 800 - 1200 in the 5 - 14 μm range.The availability of the XD modes during a given Cycle is published in the Call-for-Proposals.

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