1911 Encyclopædia Britannica/Apse and Apsides
|←Apse||1911 Encyclopædia Britannica, Volume 2
Apse and Apsides
|See also Apsis on Wikipedia; and our 1911 Encyclopædia Britannica disclaimer.|
APSE and APSIDES, in mechanics, either of the two points of an orbit which are nearest to and farthest from the centre of motion. They are called the lower or nearer, and the higher or more distant apsides respectively. The “line of apsides” is that which joins them, forming the major axis of the orbit.