Apsides: periapse and apoapse

General orbits are ellipses, with the central body orbited at one focus of the ellipse. The orbital ellipse is nearest to the central body at periapse, and farthest 180 degrees around the orbit at apoapse.

If the central body is the Earth, periapse is called perigee, and apoapse is called apogee. For other bodies:

Central body

peri = near

apo = far

general

periapse

apoapse

Earth

perigee

apogee

Moon (as "Luna")

perilune

apolune

Moon (as "Selene")

periselene

aposelene

Moon (as "??????")

pericynthion

apocynthion

Sun (as "Helios")

perihelion

aphelion

Star ( as "astra")

periastron

apastron

Apsides (last edited 2017-04-16 03:44:51 by KeithLofstrom)