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

Lunar occultation of Aldebaran

Dominic Ford, Editor
From the Lunar Occultations feed

Objects: Aldebaran

The Moon will pass in front of Aldebaran (Alpha Tauri), creating a lunar occultation visible from Canada and the eastern Contiguous United States. 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, 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 Aldebaran (Alpha Tauri) 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 Aldebaran (Alpha Tauri) 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 Aldebaran (Alpha Tauri).

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)
Canada 08:32–09:32
The Contiguous United States 08:32–08:54

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 Aldebaran (Alpha Tauri) at the moment of the occultation will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
Aldebaran (Alpha Tauri) 04h35m50s 16°30'N Taurus 1.0 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
31 Dec 2017 19 Apr 2018 Occultations of Aldebaran (Alpha Tauri) 06 Aug 2018 12 Oct 2033
01 Mar 2018 24 Apr 2018 Occultations 06 Aug 2018 18 Feb 2020

The sky on 10 Jul 2018

The sky on 10 July 2018
Sunrise
05:14
Sunset
20:22
Twilight ends
22:31
Twilight begins
03:04

27-day old moon
Waning Crescent

7%

27 days old

Planets
Rise Culm. Set
Mercury 07:31 14:37 21:42
Venus 08:50 15:41 22:32
Moon 02:59 10:17 17:41
Mars 21:50 02:19 06:47
Jupiter 15:05 20:12 01:20
Saturn 19:13 23:48 04:23
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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Cambridge

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