Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2244–2245 apparition of Mars

23 Nov 2244 – Mars enters retrograde motion
27 Dec 2244 – Mars at perigee
02 Jan 2245 – Mars at opposition
08 Feb 2245 – 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:

07 Nov 2244
11.7"
05 Dec 2244
14.4"
02 Jan 2245
15.5"
30 Jan 2245
13.1"
27 Feb 2245
10.0"

Observing Mars

Mars leaves retrograde motion as its 2244–2245 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 17:33 (PST), 50° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:34, 82° above your southern horizon. It will continue to be observable until around 03:05, when it sinks below 8° 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
24 Oct 224406h56m10s23°35'N10.5”-0.2
07 Nov 224407h13m00s23°41'N11.7”-0.5
21 Nov 224407h20m40s24°05'N13.0”-0.8
05 Dec 224407h17m00s24°53'N14.4”-1.1
19 Dec 224407h01m30s25°57'N15.4”-1.4
02 Jan 224506h38m10s26°52'N15.5”-1.6
16 Jan 224506h15m30s27°14'N14.6”-1.3
30 Jan 224506h01m50s27°08'N13.1”-0.9
13 Feb 224505h59m40s26°51'N11.4”-0.4
27 Feb 224506h07m50s26°31'N10.0”-0.1
13 Mar 224506h24m00s26°07'N8.7”0.3

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 05h59m10s 26°58'N Taurus -0.6 12.0"

The coordinates above are given in J2000.0.

The sky on 8 Jan 2026

The sky on 8 January 2026
Sunrise
06:56
Sunset
16:58
Twilight ends
18:27
Twilight begins
05:27


Waning Gibbous

64%

20 days old

Planets
Rise Culm. Set
Mercury 06:32 11:24 16:16
Venus 07:03 12:00 16:56
Moon 21:58 04:13 10:19
Mars 07:02 11:58 16:54
Jupiter 16:59 00:07 07:14
Saturn 10:34 16:27 22:21
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

08 Feb 2245  –  Mars ends retrograde motion
29 Dec 2246  –  Mars enters retrograde motion
05 Feb 2247  –  Mars at perigee
07 Feb 2247  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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