Astronomical coordinate systems are coordinate systems used in astronomy to describe the location of objects in the sky and in the universe. The most commonly occurring such systems are coordinate systems on the celestial sphere, but extragalactic coordinates systems are also important for describing more distant objects.

Coordinate systems on the celestial sphere

See Celestial coordinate system.

• Horizontal coordinate system
• Equatorial coordinate system - based on Earth rotation
• Meridional coordinate system
• Ecliptic coordinate system - based on Solar System rotation
• Galactic coordinate system - based on Milky Way rotation

Extragalactic coordinate systems

See Extragalactic astronomy.

• supergalactic coordinate system - based on plane of local supercluster of galaxies
• comoving coordinates - valid to particle horizon