AS101 Lecture Notes - Lecture 6: Axial Tilt, Orbital Eccentricity, Angular Diameter
Venus"s orbital radius averages 0. 723 au and has an orbital eccentricity of 0. 0068, almost a perfect circle. As a planet closer to the sun than earth, we, on earth, see it as always being fairly close to the sun and so view it best during the early morning or late evening. Its greatest elongation (both eastern and western) is 47 away from sun. During an inferior conjunction it is possible to have a solar transit of venus. Not every such conjunction results in a transit as its planetary orbit is inclined at 3. 39 to ecliptic. The most recent one was last june 6: the next on will be in 2117 (good luck!). Solar transits by venus are separated by more than a century and always come in pairs, about 8 years apart. There is a great article in the february, 2004 issue of sky and telescope about solar transits by venus. Venus" rotation is retrograde, meaning it rotates backwards.