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Radiation of Venus at 13.5-mm water-vapor line

1965; The National Institute of Standards and Technology; Volume: 69D; Issue: 12 Linguagem: Inglês

10.6028/jres.069d.176

2376-5771

J. E. Gibson, H. H. Corbett,

Astro and Planetary Science

A 30-ft diam altazimuth radio telescope at the Goldstone Tracking Station was used.The radiometer was a conventio nal superheterodyne radiometer with a backward-wave oscillator as th e loca l oscillator, which permitted freque nc y scanning from 20.5 to 24.0 Gels.On-off observation s were made of Venus throughout th e day, with frequent changes of the frequency observed.Extinction was meas ure d using th e Moon as a radio source.It was found, however, that extremely accurate extinction values for all fre qu e ncies cou ld be derived from th e th eory of Barrett and Chung, us ing th e radiosonde mea s ure me nt s mad e at th e Edwards Air Force Base some 50 miles from the observing site.Meas urem e nt s were made of th e antenna gai n, using a remote tran smitter at a relatively hi gh elevat ion on Tiefort Mountain.Alth ough th ese measurements were en tirely self-consis te nt , th ey differed mark edly from th eoreti cal predictions of th e a nt enna gain as a function of frequency , thu s producing so me un certainty as to th e tru e value of a nt en na gain.Measurements were made at eight di scre te freq uencies between 20.5 and 24.0 Gels.The results givc no cvidence for the pres e nce of th e water-vapor lin e.An upper limit on th e line intensity, us ing three standard deviations as a criterion, is 10 percent.Di sc uss ion Following F. D. Drake's Paper c. Sagan: What is the maximum permissible depress ion in the radio spectrum, as allowed by your results?F. D.