Lunar occultation of Sigma Sagittarii

Dominic Ford, Editor
From the Lunar Occultations feed


Objects: Nunki

The Moon will pass in front of Sigma Sagittarii (Nunki), creating a lunar occultation visible from Australia and 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 Sigma Sagittarii (Nunki) 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.

Outside the contours, the Moon will not pass in front of Sigma Sagittarii (Nunki) 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.

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

Country Time span
(UTC)
Australia 19:07–21:05
Tanzania 16:59–17:56
Mozambique 16:59–18:01
Zambia 16:59–17:56
South Africa 17:12–17:59
Madagascar 17:03–18:13
Botswana 17:09–17:57
Zimbabwe 17:03–17:59
Kenya 17:01–17:46
Democratic Republic of the Congo 16:59–17:55
Malawi 16:59–17:59
Indonesia 20:03–20:58
Somalia 17:08–17:38
Swaziland 17:18–17:58
Namibia 17:08–17:55
East Timor 20:09–20:45
Angola 17:09–17:54
Mauritius 17:12–18:19
Reunion 17:11–18:18
Uganda 17:01–17:43
Comoros 17:01–17:58
Seychelles 17:03–17:54
Mayotte 17:02–17:59
Lesotho 17:34–17:48

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 Sigma Sagittarii (Nunki) at the moment of the occultation will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
Sigma Sagittarii (Nunki) 18h55m10s 26°17'S Sagittarius 2.1 0'00"

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 Nov 2002 19 May 2003 Occultations of Sigma Sagittarii (Nunki) 13 Jul 2003 25 Jun 2021
09 Nov 2002 29 May 2003 Occultations 13 Jul 2003 17 Jul 2003

The sky on 17 Jul 2024

The sky on 17 July 2024
Sunrise
05:20
Sunset
20:17
Twilight ends
22:22
Twilight begins
03:14


Waxing Gibbous

85%

12 days old

Planets
Rise Culm. Set
Mercury 07:39 14:36 21:32
Venus 06:19 13:39 20:59
Moon 17:18 21:41 01:58
Mars 01:26 08:42 15:58
Jupiter 02:12 09:40 17:08
Saturn 22:43 04:23 10:03
All times shown in EDT.

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.

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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