FORCAST: the first light instrument for SOFIA

ABSTRACT FORCAST has been selected to be the “first light” U.S. science instrument aboard SOFIA. FORCAST will offer dual channel imaging in discrete filters at 5 - 25 microns and 30 - 40 microns, with diffraction-limited imaging at wavelengths > 15 microns. FORCAST will have a plate scale of 0.75 arcsec per pixel, giving it a 3.2 arcmin x 3.2 arcmin FOV on SOFIA. We give a status update on FORCAST, including filter configuration for SOFIA’s early science phase; anticipated in-flight performance; SOFIA facility testing with FORCAST; ground-based testing performance at Palomar Observatory; performance of its new dichroic beamsplitter; and a preliminary design of the in-flight calibration box. Keywords: Infrared cameras, blocked impurity band detectors, diamond turned optics 1. INTRODUCTION The F aint O bject infra R ed CA mera for the S ofia T elescope (FORCAST) is a dual-channel, wide-field camera designed to perform imaging in the infrared from 5-40 P m. FORCAST will be a facility instrument on the S tratospheric O bservatory F or Infrared A stronomy (SOFIA). Our focus in this paper is to report updates in anticipated in-flight performance and recent laboratory performance, and to present results from FORCAST’s second ground-based observing run on the Palomar 200-inch telescope. We begin with a very brief description of FORCAST; for a more detailed description of the instrument design, see Keller et al. (2002)