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The Far Infrared Absolute Spectraphotometer (FIRAS) instrument, one of three on NASA's Cosmic Background Explorer (COBE) satellite, was tasked with the detailed measurement of spectrum of the relict radiation of the big bang, the Cosmic Microwave Background (CMB). The instrument was a differential Michelson interferometer, covering a frequency range from 2 to 100 inverse centemeters (100 micrometers to 5000 micrometers in wavelength), with a spectral resolution of 0.4 inverse centimeters. The spatial resolution was a 7 degree diameter top-hat. Over 95\%\ of the sky was observed during the 10 month cryogenic operation of the instrument. We present a number of maps and spectra that summarize the data from the FIRAS recently made available to the community via the National Space Science Data Center at Goddard. These include the detailed spectrum of the CMB, typical galactic emission forms, and maps of the distribution of galactic dust, atomic and molecular line emission, and variations in the CMB temperature.
The National Aeronautics and Space Administration / Goddard Space Flight Center (NASA/GSFC) is reponsible for the design, development, and operation of the Cosmic Background Explorer. GSFC is also responsible for the development of the analysis software and for the production of the mission datasets. The COBE program is supported by the Astrophysics Division of NASA's Office of Space Science.
