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

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 Americas. 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 Washington, though it will be visible from eastern parts of the Contiguous United States.

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.

Map showing where the occultation is visible

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)
Mexico 02:10–04:37
Colombia 03:26–05:10
Venezuela 03:48–05:14
The Contiguous United States 02:45–04:45
Peru 03:43–04:49
Ecuador 02:57–04:50
Brazil 04:08–05:01
Cuba 03:27–05:04
Nicaragua 03:10–04:51
Guyana 04:22–05:10
Honduras 03:06–04:49
Guatemala 02:58–04:36
Panama 03:22–05:00
Costa Rica 03:14–04:52
Dominican Republic 03:51–05:14
Haiti 03:46–05:09
Bahamas 03:43–05:06
Belize 03:08–04:36
El Salvador 03:04–04:40
Jamaica 03:38–05:02
Suriname 04:39–04:59
Puerto Rico 04:00–05:16
Trinidad and Tobago 04:15–05:15
Guadeloupe 04:10–05:19
Saint Vincent and the Grenadines 04:13–05:17
Turks and Caicos Islands 03:53–05:09
Barbados 04:16–05:18
British Virgin Islands 04:04–05:17
Cayman Islands 03:31–04:51
Martinique 04:12–05:19
Curacao 03:57–05:12
Saint Kitts and Nevis 04:08–05:19
Saint Lucia 04:12–05:18
U.S. Virgin Islands 04:04–05:17
Antigua and Barbuda 04:09–05:19
Dominica 04:11–05:19
Anguilla 04:07–05:19
Bonaire, Saint Eustatius and Saba 03:59–05:18
Grenada 04:13–05:17
Bermuda 04:07–05:04
Montserrat 04:09–05:19
Aruba 03:55–05:11
Sint Maarten 04:07–05:19
Saint Barthelemy 04:07–05:19
Saint Martin 04:07–05:18
Clipperton Island 02:08–03:38
Navassa Island 03:45–05:04

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
25 Jun 2021 22 Jul 2021 Occultations of Sigma Sagittarii (Nunki) 15 Sep 2021 20 Jun 2027
25 Jun 2021 16 Aug 2021 Occultations 12 Sep 2021 03 Nov 2021

The sky on 18 Aug 2021

The sky on 18 August 2021
Sunrise
06:50
Sunset
20:21
Twilight ends
21:56
Twilight begins
05:15

10-day old moon
Waxing Gibbous

89%

10 days old

Planets
Rise Culm. Set
Mercury 08:11 14:38 21:06
Venus 09:53 15:55 21:56
Moon 17:55 22:40 03:27
Mars 08:13 14:40 21:07
Jupiter 20:24 01:45 07:06
Saturn 19:28 00:31 05:35
All times shown in MDT.

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.

Share

Washington

Latitude:
Longitude:
Timezone:

37.13°N
113.51°W
MDT

Color scheme