© NASA/Hubble Space Telescope

Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed

Objects: Mars
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Mars will reach the end of its retrograde motion, ending its westward movement through the constellations and returning to more usual eastward motion instead. This reversal of direction is a phenomenon that all the solar system's outer planets periodically undergo, a few months after they pass opposition.

The retrograde motion is caused by the Earth's own motion around the Sun. As the Earth circles the Sun, our perspective changes, and this causes the apparent positions of objects to move from side-to-side in the sky with a one-year period. This nodding motion is super-imposed on the planet's long-term eastward motion through the constellations.

The diagram below illustrates this. The grey dashed arrow shows the Earth's sight-line to the planet, and the diagram on the right shows the planet's apparently movement across the sky as seen from the Earth:


The retrograde motion of Mars. Not drawn to scale.

2041–2042 apparition of Mars

28 Dec 2041 – Mars enters retrograde motion
05 Feb 2042 – Mars at perigee
06 Feb 2042 – Mars at opposition
18 Mar 2042 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2041–2042 apparition comes to an end, although it will remain visible for some weeks in the dusk sky.

Its celestial coordinates as it leaves retrograde motion will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 08h43m50s 21°46'N Cancer -0.3 11.1"

The coordinates above are given in J2000.0.

From Fairfield , it will be visible in the evening sky, becoming accessible around 19:25 (EDT), 53° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:49, 70° above your southern horizon. It will continue to be observable until around 04:16, when it sinks below 9° above your western horizon.

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Over the following weeks, Mars will reach its highest point in the sky four minutes earlier each night, gradually disappearing into evening twilight.

The panels below show the month-by-month change in Mars' apparent size in coming weeks, as it recedes from the Earth:

Mars
21 Jan 2042
Mars
18 Feb 2042
Mars
18 Mar 2042
Mars
15 Apr 2042
Mars
13 May 2042

The table below lists Mars' angular size at brightness at two-week intervals throughout its apparition:

Date Angular size Mag
07 Jan 204212.4”-0.7
21 Jan 204213.5”-1.0
04 Feb 204213.9”-1.2
18 Feb 204213.5”-1.0
04 Mar 204212.4”-0.7
18 Mar 204211.1”-0.3
01 Apr 20429.8”0.0
15 Apr 20428.7”0.3
29 Apr 20427.8”0.6
13 May 20427.1”0.8
27 May 20426.5”1.0

The sky on 28 Mar 2024

The sky on 28 March 2024
Sunrise
06:40
Sunset
19:13
Twilight ends
20:47
Twilight begins
05:06

18-day old moon
Waning Gibbous

86%

18 days old

Planets
Rise Culm. Set
Mercury 07:08 13:57 20:46
Venus 06:08 11:53 17:38
Moon 21:47 02:58 08:00
Mars 05:29 10:52 16:16
Jupiter 08:21 15:22 22:23
Saturn 05:52 11:26 17:00
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.

Related news

18 Mar 2042  –  Mars ends retrograde motion
31 Jan 2044  –  Mars enters retrograde motion
11 Mar 2044  –  Mars at opposition
14 Mar 2044  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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Fairfield

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41.14°N
73.26°W
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