Editing Equatorial coordinate system (section)

=== Use in astronomy ===
[[File:Equatorial_and_horizontal_celestial_coordinates_E.svg|350px|thumb|Equatorial (red) and horizontal (blue) celestial coordinates]]
A [[star]]'s spherical coordinates are often expressed as a pair, [[right ascension]] and [[declination]], without a [[distance]] coordinate. The direction of sufficiently distant objects is the same for all observers, and it is convenient to specify this direction with the same coordinates for all. In contrast, in the [[horizontal coordinate system]], a star's position differs from observer to observer based on their positions on the Earth's surface, and is continuously changing with the Earth's rotation.

[[Telescope]]s equipped with [[equatorial mount]]s and [[setting circles]] employ the equatorial coordinate system to find objects. Setting circles in conjunction with a [[star chart]] or [[ephemeris]] allow the telescope to be easily pointed at known objects on the celestial sphere.