title: Radio sources: angular size from scintillation studies.
abstract: The frequency spectrum of fluctuations caused by interplanetary scintillations may give a sensitive estimate of the diameter of a radio source. Observations of 3C 138, 3C 245, 3C 267, and 3C 273 give diameters of 0.1, </=0.04, </= 0.2, and </= 0.02 second of arc, respectively. Resolution is at least a factor of 5 higher than that obtained to date by means of either radio interferometers or lunar occulations.
authors.forename: M H
authors.initials: MH
authors.lastname: Cohen
authors.forename: E J
authors.initials: EJ
authors.lastname: Gundermann
authors.forename: H E
authors.initials: HE
authors.lastname: Hardebeck
authors.forename: D E
authors.initials: DE
authors.lastname: Harris
authors.forename: E E
authors.initials: EE
authors.lastname: Salpeter
authors.forename: L E
authors.initials: LE
authors.lastname: Sharp