Conjunction

by Dominic Ford, Editor
Last updated: 15 Jul 2020
Conjunction

The Moon in conjunction with Venus and Jupiter, with the Very Large Telescope in the foreground. Image © Y. Beletsky, 2009.

A conjunction is an event when two or more astronomical bodies share the same right ascension.

In common parlance, the term is often also used to refer to any close groupings of objects. However, the technical term for such groupings is an appulse, which may or may not also be a conjunction.

As the Moon and planets move along the ecliptic at different speeds, they pass each other from time to time. In some cases this is extremely rare: Uranus and Neptune, for example, move very slowly, taking 84 and 165 years respectively to make a complete circuit through the constellations. As a result, conjunctions between the two planets only happen once every 171 years.

The Moon on the other hand moves much faster, and passes conjunction with every planet roughly once a month.

The planets are usually separated by no more than a few degrees when they are in conjunction. The planets all orbit the Sun in almost the same plane, which means that they all closely follow a common line across the sky – the ecliptic.

The Moon has a different orbital plane, however, and can deviate by up to 5° from the ecliptic. Thus, the Moon can be in conjunction with the planets without being at all close to them.

List of conjunctions

The table below lists conjunctions in 2024, computed from NASA's DE430 planetary ephemeris. To show conjunctions in other years, use the control below.

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Conjunctions in 2024

Date Object 1 Object 2 Separation Full description
of event
Date Object 1 Object 2 Separation Full description
of event
27 Jan 2024 11:06 ESTMercuryMars14'00"More information »
22 Feb 2024 10:31 ESTVenusMars38'00"More information »
21 Mar 2024 21:59 EDTVenusSaturn20'00"More information »
03 Apr 2024 06:53 EDTVenusNeptune17'00"More information »
10 Apr 2024 23:11 EDTSaturnMars28'00"More information »
20 Apr 2024 03:30 EDTJupiterUranus31'00"More information »
29 Apr 2024 00:01 EDTMarsNeptune2'14"More information »
30 May 2024 21:24 EDTMercuryUranus1°21'00"More information »
04 Jun 2024 06:04 EDTJupiterMercury7'04"More information »
15 Jul 2024 05:22 EDTMarsUranus33'00"More information »
06 Aug 2024 11:21 EDTVenusMercury5°55'00"More information »
14 Aug 2024 12:52 EDTJupiterMars18'00"More information »

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