direct motion; prograde motion
Astronomical term for the apparent eastward motion of a celestial body relative to the fixed stars, opposite of retrograde motion (逆行運動).
See also: 逆行運動
惑星の順行運動は、地球から見て東へ進むように見える。
The direct motion of a planet appears to move eastward as seen from Earth.
Direct motion and retrograde motion are fundamental concepts in astronomy.