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

Lunar occultation of Mars

Dominic Ford, Editor
From the Lunar Occultations feed

Objects: Mars

The Moon will pass in front of Mars, creating a lunar occultation visible from parts of Asia.

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.

On this occasion, no occultation will be visible from San Diego.

The map below shows the visibility of the occultation across the world. Separate contours show where the disappearance of Mars 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 of the contours, the Moon does not pass in front of Mars at any time, or is below the horizon at the time of the occultation.

The map below 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.

Map showing where the occultation is visible

The position of Mars at the moment of the occultation will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 05h42m40s 24°50'N Taurus 1.5 0'04"

The coordinates above are given in J2000.0.

The sky on 17 April 2021
Sunrise
06:15
Sunset
19:23
Twilight ends
20:47
Twilight begins
04:51

5-day old moon
Waxing Crescent

28%

5 days old

Planets
Rise Culm. Set
Mercury 06:18 12:46 19:13
Venus 06:39 13:13 19:47
Moon 09:50 17:13 00:43
Mars 09:35 16:48 00:00
Jupiter 03:33 09:01 14:28
Saturn 02:52 08:07 13:23
All times shown in PDT.

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.

Related news

13 Oct 2020  –  Mars at opposition
30 Nov 2022  –  Mars at perigee
07 Dec 2022  –  Mars at opposition
12 Jan 2025  –  Mars at perigee

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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San Diego

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32.72°N
117.16°W
PDT

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