Appulse

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

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

An appulse is when two or more astronomical objects – usually the planets or the Moon – appear close to one another in the sky.

Since the Moon moves relatively quickly across the sky, making a complete circuit through the constellations every month, most appulses occur when the Moon passes another body. These tend to recur on a monthly basis, as the Moon passes the same planets at a similar point in its cycle of phases each month.

There is no formal definition of how close two objects need to become for their close encounter to qualify as an appulse. On In-The-Sky.org, we list all appulses where planets or minor planets pass within one degree of each other. For naked-eye objects, we include appulses out to three degrees, and for particularly bright naked-eye objects, out to five degrees.

Occasionally very close appulses may result in one object passing in front of another – an event called an occultation. Most such events involve the Moon, simply because the Moon traverses such a large area of the sky each month.

Appulses vs conjunctions

In common parlance, close groupings of objects are often called conjunctions, but this term has a rather more technical meaning, referring to when two objects share the same right ascension.

List of appulses

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

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Appulses 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 11:27 ESTMercuryMars14'00"More information »
22 Feb 2024 04:46 ESTVenusMars37'00"More information »
21 Mar 2024 19:15 EDTVenusSaturn19'00"More information »
10 Apr 2024 16:35 EDTSaturnMars26'00"More information »
29 Apr 2024 00:31 EDTMarsNeptune2'03"More information »
04 Jun 2024 06:32 EDTJupiterMercury6'45"More information »
15 Jul 2024 10:25 EDTMarsUranus32'00"More information »
14 Aug 2024 10:53 EDTJupiterMars18'00"More information »

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