Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2041–2042 apparition of Mars

27 Dec 2041 – Mars enters retrograde motion
04 Feb 2042 – Mars at perigee
06 Feb 2042 – Mars at opposition
18 Mar 2042 – 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:

12 Dec 2041
10.0"
09 Jan 2042
12.5"
06 Feb 2042
13.9"
06 Mar 2042
12.3"
03 Apr 2042
9.7"

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.

As retrograde motion ends, it will be visible in the evening sky, becoming accessible around 19:22 (PST), 55° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:48, 77° above your southern horizon. It will continue to be observable until around 04:01, when it sinks below 9° above your 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
28 Nov 204109h41m00s16°21'N8.9”0.2
12 Dec 204109h55m10s15°39'N10.0”-0.1
26 Dec 204110h01m50s15°39'N11.2”-0.4
09 Jan 204209h58m40s16°31'N12.5”-0.7
23 Jan 204209h45m30s18°08'N13.6”-1.1
06 Feb 204209h24m30s20°00'N13.9”-1.2
20 Feb 204209h03m00s21°24'N13.4”-1.0
06 Mar 204208h48m20s21°57'N12.3”-0.7
20 Mar 204208h43m50s21°42'N10.9”-0.3
03 Apr 204208h49m00s20°50'N9.7”0.0
17 Apr 204209h01m40s19°30'N8.6”0.3

As it leaves retrograde motion, its celestial coordinates 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.

The sky on 24 Feb 2026

The sky on 24 February 2026
Sunrise
06:24
Sunset
17:43
Twilight ends
19:07
Twilight begins
05:01


Waxing Gibbous

59%

7 days old

Planets
Rise Culm. Set
Mercury 06:59 13:00 19:00
Venus 07:04 12:49 18:35
Moon 10:44 18:18 01:57
Mars 06:00 11:24 16:47
Jupiter 13:27 20:37 03:47
Saturn 07:41 13:39 19:38
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

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

Image credit

© NASA/Hubble Space Telescope

Share