Radar Observation of Venus

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Science  03 Nov 1961:
Vol. 134, Issue 3488, pp. 1419-1421
DOI: 10.1126/science.134.3488.1419


Radar observations of Venus during the last close approach have resulted in a value of solar parallax of 8.79460 seconds of arc, corresponding to a value for the astronomical unit of 149,596,000 km. This is in satisfactory agreement with the determinations made, during the same close approach of Venus, at the Millstone Hill Radar Observatory and at Jodrell Bank, which are 149,597,700 km and 149,601,000 km, respectively. The size of the astronomical unit heretofore generally accepted as most authoritative is based upon a 1950 determination by Rabe, and is 149,532,200 km.