Study of Venus by CW radar-1964 results

During the 1964 conjunction of Venus, the planet was observed by radar on a daily basis with an 85-ft dish at the NASA/JPL Deep Space Instrumentation Facility at Goldstone, California. The wavelength was 12.5 cm and the transmitter power was 100 kW. The results of one phase of the program are discussed- those of the high-resolution cw radar spectra. The polarized reflectivity obtained is 0.114+0.01. The de- polarized reflectivity is 0.0067+0.0005. The estimated average dielectric constant of Venus' surface is 3.75+0.3. The base bandwidth of the spectra gives a retrograde sidereal rotation of 250 days +4, -7 days. The direction of the north polar axis is estimated to be a=2SS +lO , -4 and =680+4 . This places the axis within 10 of the orbit pole. Several spectral features were found and their positions on Venus' surface is derived. A comparison of the 1964 features with the features observed in 1962 suggesta that the rotation of Venus may be nearer to 244 days retrograde rather than 250 days given by the base bandwidth measure- ments.