Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2056–2057 apparition of Mars

14 Dec 2056 – Mars enters retrograde motion
21 Jan 2057 – Mars at perigee
23 Jan 2057 – Mars at opposition
04 Mar 2057 – Mars ends retrograde motion

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.

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

28 Nov 2056
10.4"
26 Dec 2056
13.0"
23 Jan 2057
14.3"
20 Feb 2057
12.4"
20 Mar 2057
9.7"

Observing Mars

Mars leaves retrograde motion as its 2056–2057 apparition comes to an end, although it will remain visible for some weeks in the dusk sky.

As retrograde motion ends, it will be visible in the evening sky, becoming accessible around 18:09 (PST), 54° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:46, 80° above your southern horizon. It will continue to be observable until around 03:09, when it sinks below 9° above your north-western horizon.

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

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

Date Right ascension Declination Angular size Magnitude
14 Nov 205608h46m10s19°57'N9.3”0.1
28 Nov 205609h01m10s19°29'N10.4”-0.2
12 Dec 205609h08m10s19°37'N11.7”-0.5
26 Dec 205609h04m50s20°29'N13.0”-0.8
09 Jan 205708h50m40s22°00'N14.0”-1.1
23 Jan 205708h28m40s23°38'N14.3”-1.3
06 Feb 205708h06m30s24°44'N13.6”-1.1
20 Feb 205707h51m50s25°03'N12.4”-0.7
06 Mar 205707h48m00s24°46'N11.0”-0.3
20 Mar 205707h54m10s24°02'N9.7”0.0
03 Apr 205708h08m00s22°57'N8.6”0.4

As it leaves retrograde motion, its celestial coordinates will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 07h47m50s 24°51'N Gemini -0.4 11.2"

The coordinates above are given in J2000.0.

The sky on 10 Jan 2026

The sky on 10 January 2026
Sunrise
06:56
Sunset
17:00
Twilight ends
18:29
Twilight begins
05:27


Waning Crescent

46%

21 days old

Planets
Rise Culm. Set
Mercury 06:38 11:30 16:22
Venus 07:05 12:03 17:00
Moon 23:56 05:36 11:09
Mars 07:00 11:57 16:54
Jupiter 16:46 23:54 07:01
Saturn 10:27 16:20 22:13
All times shown in PST.

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

04 Mar 2057  –  Mars ends retrograde motion
17 Jan 2059  –  Mars enters retrograde motion
26 Feb 2059  –  Mars at opposition
28 Feb 2059  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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