Planetary coordinate formula

There are two commonly used planetary coordinate formulas:

1. The celestial coordinates with the center of the planet as the origin or the center of the celestial sphere are called planetary center coordinates.

2. The coordinates of celestial bodies with the center of mass of celestial bodies (usually the solar system) as the origin or the center of the celestial sphere are called centroid coordinates.

Both coordinate systems are established by selecting the origin and direction of the coordinate axis. Among them, the planet center coordinates take the planet center as the origin, and the centroid coordinates take the celestial body system centroid as the origin. In astronomy, these coordinate systems are very important for studying the position and motion of celestial bodies.