Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2268 apparition of Mars

07 Apr 2268 – Mars enters retrograde motion
13 May 2268 – Mars at opposition
21 May 2268 – Mars at perigee
22 Jun 2268 – 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:

18 Mar 2268
10.7"
15 Apr 2268
14.3"
13 May 2268
17.2"
10 Jun 2268
16.4"
08 Jul 2268
13.5"

Observing Mars

Mars leaves retrograde motion as its 2268 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 20:10 (PST), 36° above your southern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:15, 39° above your southern horizon. It will continue to be observable until around 01:47, when it sinks below 7° above your south-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
04 Mar 226815h18m00s16°36'S9.3”0.1
18 Mar 226815h33m00s17°38'S10.7”-0.3
01 Apr 226815h41m10s18°18'S12.4”-0.7
15 Apr 226815h40m00s18°35'S14.3”-1.1
29 Apr 226815h28m50s18°26'S16.1”-1.5
13 May 226815h09m30s17°51'S17.2”-1.9
27 May 226814h49m00s17°06'S17.3”-1.7
10 Jun 226814h34m50s16°36'S16.4”-1.5
24 Jun 226814h30m40s16°42'S15.0”-1.2
08 Jul 226814h37m10s17°29'S13.5”-0.9
22 Jul 226814h52m20s18°48'S12.2”-0.6

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 14h30m40s 16°38'S Libra -1.2 15.2"

The coordinates above are given in J2000.0.

The sky on 25 Feb 2026

The sky on 25 February 2026
Sunrise
06:23
Sunset
17:44
Twilight ends
19:07
Twilight begins
05:00


Waxing Gibbous

74%

9 days old

Planets
Rise Culm. Set
Mercury 06:55 12:56 18:57
Venus 07:03 12:50 18:37
Moon 11:41 19:21 03:00
Mars 05:59 11:23 16:47
Jupiter 13:23 20:33 03:42
Saturn 07:37 13:36 19:34
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

22 Jun 2268  –  Mars ends retrograde motion
09 Jun 2270  –  Mars enters retrograde motion
11 Jul 2270  –  Mars at opposition
17 Jul 2270  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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