Accession Number : AD0450466

Title :   BROADBAND RADIO-STAR SCINTILLATIONS, PART I. OBSERVATIONS,

Corporate Author : HIGH ALTITUDE OBSERVATORY BOULDER CO

Personal Author(s) : Singleton, D. G.

Report Date : 26 MAR 1964

Pagination or Media Count : 14

Abstract : Twelve months' observations of the scintillations of Cassiopeia A made with a swept-frequency interferometer operating in the frequency range 7.6 to 41 Mc/s are examined statistically. The scintillations, which commonly have bandwidths of 2:1 and larger, are occasionally accociated with apparent shifts in the position of the source. Two types of position shift patterns are observed. These are mirror images of each other and occur during different periods of sidereal time. The broadband scintillations also occasionally exhibit dispersion. This effect is most marked before 0900 hours local sidereal time and after 0200 hours local time. The overall occurrence picture of the broadband scintillations is much as reported by other workers for scintillations observed at discrete frequencies. Broadband scintillation occurrence is found to correlate positively with the occurrence of spread-F. The focus frequency of those scintillations which exhibit position shifts is found to depend, in a simple way, on the parameters of the associated spread-F configuration. Increasing magnetic activity, which has little effect on the occurrence of the scintillations, is found to be associated with a decrease in the quasiperiod of groups of scintillations. (Author)

Descriptors :   (*STARS, RADIO ASTRONOMY), (*BRIGHTNESS, IONOSPHERE), BROADBAND, INTERFEROMETERS, RADIO SIGNALS, ASTROPHYSICS, MAGNETIC FIELDS, TIME, MEASUREMENT, ELECTRON DENSITY, PROPAGATION.

Distribution Statement : APPROVED FOR PUBLIC RELEASE