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

Conjunction of the Moon and Mercury

Dominic Ford, Editor
From the Conjunctions feed

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The sky at

The Moon and Mercury will share the same right ascension, with the Moon passing 3°41' to the south of Mercury. The Moon will be 28 days old.

From San Diego, the pair will be difficult to observe as they will appear no higher than 9° above the horizon. They will be visible in the dawn sky, rising at 04:55 (PDT) – 1 hour and 9 minutes before the Sun – and reaching an altitude of 9° above the south-eastern horizon before fading from view as dawn breaks around 05:48.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

The Moon will be at mag -9.6, and Mercury at mag 0.0, both in the constellation Capricornus.

The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

A graph of the angular separation between the Moon and Mercury around the time of closest approach is available here.

The positions of the two objects at the moment of conjunction will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
The Moon 21h45m00s -18°26' Capricornus -9.6 30'45"3
Mercury 21h45m00s -14°44' Capricornus 0.0 6"6

The coordinates above are given in J2000.0. The pair will be at an angular separation of 28° from the Sun, which is in Aquarius at this time of year.

The sky on 10 March 2021
Twilight ends
Twilight begins

27-day old moon
Waning Crescent


27 days old

Rise Culm. Set
Mercury 04:57 10:21 15:45
Venus 06:03 11:48 17:34
Moon 04:50 10:06 15:24
Mars 09:35 16:39 23:43
Jupiter 04:41 10:02 15:23
Saturn 04:09 09:23 14:36
All times shown in PST.


The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

06 Mar 2021  –  Mercury at greatest elongation west
17 May 2021  –  Mercury at highest altitude in evening sky
17 May 2021  –  Mercury at greatest elongation east
04 Jul 2021  –  Mercury at greatest elongation west

Image credit

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



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