title: Far-infrared surveys of the sky.
abstract: A series of far-infrared surveys of the sky is searching for thermal radiation from interstellar grains and for other localized sources of far-infrared radiation. A balloon-borne germanium bolometer, cooled by liquid helium, is used in association with a telescope and spectral filters. During two initial flights the response to a black-body source was mainly between 300 and 360 microns. Approximately half the celestial sphere was surveyed, including most of the northern Milky Way. The angular resolution was 2 degrees. Moon was the only source of thermal radiation detected. The upper limit on the differential flux, relative to background, from other sources was 2 x 10(-23) watt per square centimeter per hertz, corresponding to an antenna temperature of 0.6 degrees K in the Rayleigh-Jeans approximation, or 10 degrees K for a black body.
authors.forename: W F
authors.initials: WF
authors.lastname: Hoffmann
authors.forename: N J
authors.initials: NJ
authors.lastname: Woolf
authors.forename: C L
authors.initials: CL
authors.lastname: Frederick
authors.forename: F J
authors.initials: FJ
authors.lastname: Low