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

The Moon will pass in front of Neptune, creating a lunar occultation visible from Sub-Saharan Africa. 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 Cambridge.

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 the contours, the Moon will 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 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 Neptune.

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
(UTC)
South Africa 18:53–20:10
Angola 19:20–20:24
Democratic Republic of the Congo 19:27–20:24
Namibia 19:00–20:18
Zambia 19:20–20:23
Botswana 19:05–20:17
Zimbabwe 19:15–20:18
Mozambique 19:09–20:19
Republic of the Congo 19:53–20:18
Swaziland 19:09–20:04
Malawi 19:22–20:06
Lesotho 19:05–19:59

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Neptune 21h28m40s 15°11'S Capricornus 7.9 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
28 Jul 1999 17 Nov 2007 Occultations of Neptune 11 Jan 2008 23 Jun 2008
03 Nov 2007 11 Dec 2007 Occultations 23 Dec 2007 24 Dec 2007

The sky on 18 May 2024

The sky on 18 May 2024
Sunrise
05:17
Sunset
20:02
Twilight ends
22:03
Twilight begins
03:16

10-day old moon
Waxing Gibbous

79%

10 days old

Planets
Rise Culm. Set
Mercury 04:26 11:06 17:46
Venus 05:09 12:21 19:33
Moon 15:14 21:22 03:19
Mars 03:30 09:48 16:07
Jupiter 05:23 12:40 19:57
Saturn 02:36 08:15 13:54
All times shown in EDT.

Warning

Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.

Source

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

31 Oct 2007  –  Neptune ends retrograde motion
26 May 2008  –  Neptune enters retrograde motion
15 Aug 2008  –  Neptune at opposition
02 Nov 2008  –  Neptune ends retrograde motion

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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