noun
galactic equator
Astronomical term for the great circle on the celestial sphere that passes through the Milky Way and is inclined to the celestial equator.
銀河赤道は天の川に沿って描かれる大円です。
The galactic equator is a great circle drawn along the Milky Way.
The celestial equator is the projection of Earth's equator onto the celestial sphere, while the galactic equator is aligned with the plane of the Milky Way.
Compound of 銀河 (ginga, 'galaxy') and 赤道 (sekidō, 'equator'). The term is a direct calque from English 'galactic equator'.