The Twilight Atmosphere of Venus

摘要

An investigation of the discrepancies between the theoretically predicted and the actually observed shape and periodic appearance of Venus. Current astronomical methods of observation of the twilight sky of Venus are investigated by combining a rigorous celestial geometry with a determination of the physical effects exerted by the relative luminances of the atmospheres of Venus and the Earth. Analysis shows that the discrepancy between the expected and observed times of dichotomy corresponds to a range in position angle from about 92 to 98 degrees, which implies a minimum height of the effectively scattering atmosphere from 13 to 23 km. There are indications that the true height may be several tens of kilometers.