descending node

…The orbital planes of planets, asteroids, comets, etc. projected onto the celestial sphere generally intersect with the ecliptic, which is taken as the reference plane, at two points. These are called intersections, and the point where the celestial body crosses the ecliptic from south to north is called the ascending node, and the point where it crosses from north to south is called the descending node. In the case of satellites, the equatorial plane of the parent planet is usually used as the reference plane instead of the ecliptic, but sometimes the orbital plane of the parent planet or the ecliptic plane is used as the reference plane. …

*Some of the terminology explanations that mention "descending node" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…天球に投影した惑星，小惑星，すい星などの軌道面は，一般に基準面として採用した黄道と2点で交わる。これらを交点と呼ぶが，そのうち，それらの天体が黄道を南から北へ横切る点を昇交点，北から南へ横切る点を降交点descending nodeという。衛星の場合には，黄道の代りに，母惑星の赤道面を基準面として採用して定義するのがふつうであるが，母惑星の公転軌道面や黄道面を基準とする場合もある。…

※「descending node」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報