Conjunction (def): The occasion when two celestial bodies align on the celestial sphere; this is their least angular separation based on the view from Earth. Examples are when two planets appear together in the night sky as one passes by the other in their orbit around the Sun, or when the Moon passes by one or more planets and these appear together in the sky.

Other conjunctions involve the Sun. These are called inferior and superior conjunctions. An inferior conjunction is when an inner planet and Sun align from the perspective of Earth, with the inner planet between the Sun and the Earth. Compare this to a superior conjunction when an inner or outer planet and Sun align with the planet this time positioned behind the Sun (see diagram).


For also: Interesting Conjunctions.

« Back to Glossary Index