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, Mexico and western Guatemala. 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 Cambridge. It will begin with the disappearance of Sigma Sagittarii (Nunki) behind the Moon at 07:22 EST, though in daylight. Its reappearance will be visible at 08:42 EST, though in daylight.

Extreme caution is necessary when pointing binoculars or telescopes at the sky when the Sun is above the horizon, as even a momentary glance at the Sun through such an instrument can cause permanent blindness.

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 11:02–12:57
Mexico 11:00–12:48
Guatemala 11:28–12:41

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 0 days past new moon and will be 31% illuminated. Sigma Sagittarii (Nunki) will disappear behind the illuminated side of the Moon and reappear from behind the unilluminated 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
20 Nov 1952 11 Feb 1953 Occultations of Sigma Sagittarii (Nunki) 06 Apr 1953 19 May 1965
20 Nov 1952 08 Mar 1953 Occultations 04 Apr 1953 28 Oct 1953

The sky on 23 Nov 2024

The sky on 23 November 2024
Sunrise
06:43
Sunset
16:15
Twilight ends
17:54
Twilight begins
05:03


Waning Crescent

42%

22 days old

Planets
Rise Culm. Set
Mercury 08:33 12:55 17:17
Venus 10:09 14:32 18:54
Moon 23:09 06:06 12:50
Mars 20:36 04:03 11:30
Jupiter 17:09 00:40 08:11
Saturn 12:58 18:29 23:59
All times shown in EST.

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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