noun
In astronomy, the angular distance of a planet or other body from its perihelion (or periapsis) as seen from the sun (or central body). A technical term used in celestial mechanics.
ケプラーの方程式を使って、惑星の近点角を計算する。
Calculate the planet's anomaly using Kepler's equation.
Compound of 近点 (periapsis) + 角 (angle). The exact historical derivation is uncertain; the term is a modern technical coinage.