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

Lunar occultation of Mercury

Dominic Ford, Editor
From the Lunar Occultations feed

Objects: Mercury

The Moon will pass in front of Mercury, creating a lunar occultation visible from countries and territories including Canada, western Russia, Greenland and Alaska amongst others. Although the occultation will only be visible across part of the world – because the Moon is so close to the Earth that its position in the sky varies by as much as two degrees across the world – a close conjunction between the pair will be more widely visible.

Unfortunately the occultation will not be visible from Ashburn, though it will be visible from western parts of the Contiguous United States.

The map below shows the visibility of the occultation across the world. Separate contours show where the disappearance of Mercury is visible (shown in red), and where its reappearance is visible (shown in blue). Solid contours show where each event is likely to be visible through binoculars at a reasonable altitude in the sky. Dotted contours indicate where each event occurs above the horizon, but may not be visible due to the sky being too bright or the Moon being very close to the horizon.

Map showing where the occultation is visible

Outside the contours, the Moon will not pass in front of Mercury at any time, or is below the horizon at the time of the occultation. However, a close conjunction between the pair will be visible across much of the world.

The map can be downloaded in PNG , PDF or SVG format. A KMZ file , is also available, which can be opened in Google Earth to provide a higher resolution map.

The animation below shows the path of the occultation across the Earth's globe. The red circle shows where the Moon appears in front of Mercury.

You can download this video in MP4 or OGG format.

A complete list of the countries and territories where the occultation will be visible is as follows:

Country Time span
Canada 13:39–04:37
Russia 21:03–22:05
Greenland 02:08–20:33
Alaska 13:39–04:19
Finland 20:54–05:13
Sweden 21:03–05:16
The Contiguous United States 14:03–04:43
Norway 21:09–05:10
Kazakhstan 21:04–18:35
Svalbard 03:00–20:27
Estonia 02:44–05:18
Latvia 02:37–05:21
Belarus 02:47–05:31
Aland Islands 18:48–05:12
Svalbard and Jan Mayen 02:53–20:17

Lunar occultations are only ever visible from a small fraction of the Earth's surface. Since the Moon is much closer to the Earth than other celestial objects, its exact position in the sky differs depending on your exact location on Earth due to its large parallax. The position of the Moon as seen from two points on opposite sides of the Earth varies by up to two degrees, or four times the diameter of the full moon.

This means that if the Moon is aligned to pass in front of a particular object for an observer on one side of the Earth, it will appear up to two degrees away from that object on the other side of the Earth.

The position of Mercury at the moment of the occultation will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mercury 06h40m00s 22°23'N Gemini -0.7 0'06"

The coordinates above are given in J2000.0.

Next/previous occultations

« Previous Next »
Visible from the Contiguous United States Worldwide Worldwide Visible from the Contiguous United States
09 Jun 1983 29 Jul 2000 Occultations of Mercury 25 Nov 2003 03 Nov 2021
17 Jul 2001 17 Jul 2001 Occultations 14 Aug 2001 15 Aug 2001

The sky on 24 Sep 2023

The sky on 24 September 2023
Twilight ends
Twilight begins

9-day old moon
Waxing Gibbous


9 days old

Rise Culm. Set
Mercury 05:29 11:57 18:25
Venus 03:37 10:17 16:58
Moon 16:32 21:11 01:56
Mars 08:22 14:03 19:44
Jupiter 20:55 03:48 10:41
Saturn 17:50 23:11 04:33
All times shown in EDT.


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

14 Jul 2001  –  Mercury at highest altitude in morning sky
07 Sep 2001  –  Mercury at highest altitude in evening sky
18 Sep 2001  –  Mercury at greatest elongation east
29 Oct 2001  –  Mercury at highest altitude in morning sky

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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