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

Lunar occultation of Regulus

Dominic Ford, Editor
From the Lunar Occultations feed

Objects: Regulus

The Moon will pass in front of Regulus (Alpha Leonis), creating a lunar occultation visible from countries and territories including Canada, Greenland, Alaska and Iceland amongst others. 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 Ashburn, 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 Regulus (Alpha Leonis) 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 Regulus (Alpha Leonis) 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
Canada 13:39–00:51
Greenland 02:08–04:21
Alaska 13:39–11:27
Iceland 02:30–04:51
Ireland 02:40–02:08
The Contiguous United States 14:03–00:51
Great Britain 02:45–02:11
Northern Ireland 02:44–02:06
Faroe Islands 02:49–04:56
The Portuguese Azores 02:16–05:03
Svalbard and Jan Mayen 02:53–04:50
Saint Pierre and Miquelon 02:04–00:45

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 Regulus (Alpha Leonis) at the moment of the occultation will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
Regulus (Alpha Leonis) 10h08m20s 11°58'N Leo 1.4 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
15 Oct 2017 01 Feb 2018 Occultations of Regulus (Alpha Leonis) 28 Mar 2018 03 Feb 2026
31 Dec 2017 23 Feb 2018 Occultations 22 Mar 2018 10 Jul 2018

The sky on 1 Mar 2018

The sky on 1 March 2018
Twilight ends
Twilight begins

14-day old moon
Waxing Gibbous


14 days old

Rise Culm. Set
Mercury 07:11 13:01 18:50
Venus 07:18 13:09 18:59
Moon 17:47 00:32 07:13
Mars 02:07 06:51 11:34
Jupiter 23:52 04:56 10:00
Saturn 03:18 08:03 12:48
All times shown in EST.


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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