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 the Contiguous United States, Canada and Mexico. 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.

The occultation will be visible from Jacksonville. It will begin with the disappearance of Sigma Sagittarii (Nunki) behind the Moon at 01:03 EDT in the south-western sky at an altitude of 27.4 degrees. Its reappearance will be visible at 01:44 EDT at an altitude of 22.7 degrees.

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)
The Contiguous United States 03:18–06:00
Canada 03:29–06:00
Mexico 03:28–05:20

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 6 days past new moon and will be 91% illuminated. Sigma Sagittarii (Nunki) will disappear behind the unilluminated side of the Moon and reappear from behind the illuminated side of the Moon.

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
19 May 1965 12 Jul 1965 Occultations of Sigma Sagittarii (Nunki) 05 Sep 1965 08 Jul 1971
27 Jun 1965 05 Aug 1965 Occultations 01 Sep 1965 27 Jul 1966

The sky on 17 Jul 2024

The sky on 17 July 2024
Sunrise
06:33
Sunset
20:28
Twilight ends
22:02
Twilight begins
04:59


Waxing Gibbous

84%

12 days old

Planets
Rise Culm. Set
Mercury 08:41 15:18 21:55
Venus 07:29 14:21 21:12
Moon 17:20 22:24 03:26
Mars 02:35 09:24 16:13
Jupiter 03:26 10:22 17:18
Saturn 23:18 05:06 10:53
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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