A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2021 Mar 11, 16:47 -0800
Oops. I forgot one other easy method to distinguish "near" Venus from "far" Venus. You look at Venus through a small telescope. If it is a crescent, less than 50% illuminated, then it is on the near side of its orbit, more specifically the portion of the orbit close to the Earth between the extremes of greatest elongation on either side of the Sun.If you could look at Venur through a telescope this week, approaching superior conjunction, you would find that it is a nearly perfect disk, like a tiny Full Moon. If you looked at Venus through a telescope in a several months-long period centered on inferior conjunction, you would have seen a crescent phase. The phases, in the context of celestial navigation, also determine the periods when you need to distinguish between "center of light" and "center of body". Around inferior conjucntion, at low magnification, the bright "spot" of light that we see as Venus is displaced slightly towards the leading limb of the crescent and away from the center of the circular disk of the planet.