title: Spectral line interferometry with independent time standards at stations separated by 845 kilometers.
abstract: An upper limit of 0.02 second of arc has been determined for a hydroxyl radical (OH) emission region associated with the radio source W3, with the use of a Michelson interferometer consisting of two radio telescopes 845 kilometers apart. Timing was provided at the stations by independent atomic frequency standards. The 1665-megahertz radiation was translated to video frequency and recorded digitally on magnetic tapes which were later processed by computer, yielding fringe phase and amplitude as a function of frequency over the received bandwidth.
authors.forename: J M
authors.initials: JM
authors.lastname: Moran
authors.forename: P P
authors.initials: PP
authors.lastname: Crowther
authors.forename: B F
authors.initials: BF
authors.lastname: Burke
authors.forename: A H
authors.initials: AH
authors.lastname: Barrett
authors.forename: A E
authors.initials: AE
authors.lastname: Rogers
authors.forename: J A
authors.initials: JA
authors.lastname: Ball
authors.forename: J C
authors.initials: JC
authors.lastname: Carter
authors.forename: C C
authors.initials: CC
authors.lastname: Bare