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

Lunar occultation of Neptune

Dominic Ford, Editor
From the Lunar Occultations feed

Objects: Neptune
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The Moon will pass in front of Neptune, creating a lunar occultation visible from countries and territories including Canada, the Contiguous United States, Mexico and south-eastern Alaska amongst others.

The occultation will be visible from Cambridge. It will begin with the disappearance of Neptune behind the Moon at 04:10 EDT in the south-western sky at an altitude of 26.6 degrees. Its reappearance will be visible at 04:35 EDT at an altitude of 22.5 degrees.

The map below shows the visibility of the occultation across the world. Separate contours show where the disappearance of Neptune 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 of the contours, the Moon does not pass in front of Neptune at any time, or is below the horizon at the time of the occultation. However, a close conjunction between the pair may be visible.

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.

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

Country Time span
Canada 18:42–19:05
The Contiguous United States 02:31–18:51
Mexico 17:22–08:59
Alaska 15:38–12:21
Hawaii 15:43–09:57
Kiribati 15:23–06:40
Kingman Reef 15:29–06:25
Palmyra Atoll 15:29–06:28
Midway Atoll 15:46–09:42
Cook Islands 02:22–07:15
Jarvis Island 01:12–06:47

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.

At the time of the occultation, the Moon will be 25 days past new moon and will be 100% illuminated. Neptune will disappear behind the illuminated side of the Moon and reappear from behind the illuminated side of the Moon.

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Neptune 23h55m40s 1°54'S Pisces 7.8 0'02"

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
06 Dec 2016 21 Aug 2024 Occultations of Neptune 15 Oct 2024 12 Nov 2024
14 Jul 2024 10 Sep 2024 Occultations 24 Sep 2024 21 Oct 2024

The sky on 18 Sep 2024

The sky on 18 September 2024
Twilight ends
Twilight begins

15-day old moon
Waning Gibbous


15 days old

Rise Culm. Set
Mercury 05:31 12:01 18:31
Venus 08:52 14:22 19:51
Moon 18:44 00:42 06:55
Mars 23:49 07:26 15:03
Jupiter 22:39 06:11 13:42
Saturn 18:24 23:57 05:31
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.

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25 Sep 2026  –  Neptune at opposition

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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