Elongation of a Planet

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Elongation of a Planet

 

the position of an inferior planet (Venus or Mercury) at the time when its longitude differs maximally from that of the sun. A distinction is made between the western and eastern elongations of a planet. At the time of elongation, Venus is located at an angular distance of 48° from the sun. The angular distance from Mercury to the sun at the time of elongation ranges from 18° to 28° because of the larger eccentricity of its orbit. During elongation, the planets move along the line of sight toward or away from the earth. (SeeCONFIGURATIONS.)

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.