Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2200 apparition of Mars

02 Jan 2200 – Mars enters retrograde motion
11 Feb 2200 – Mars at perigee
12 Feb 2200 – Mars at opposition
24 Mar 2200 – 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 Dec 2199
9.9"
15 Jan 2200
12.5"
12 Feb 2200
13.9"
12 Mar 2200
12.3"
09 Apr 2200
9.7"

Observing Mars

Mars leaves retrograde motion as its 2200 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 19:16 (PST), 55° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:40, 76° above your southern horizon. It will continue to be observable until around 03:50, 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
04 Dec 219909h54m40s15°17'N8.8”0.2
18 Dec 219910h08m50s14°32'N9.9”-0.1
01 Jan 220010h15m10s14°31'N11.2”-0.4
15 Jan 220010h12m20s15°21'N12.5”-0.7
29 Jan 220009h59m10s16°58'N13.5”-1.0
12 Feb 220009h38m30s18°52'N13.9”-1.2
26 Feb 220009h17m10s20°20'N13.4”-1.0
12 Mar 220009h02m30s20°55'N12.3”-0.7
26 Mar 220008h57m50s20°40'N11.0”-0.3
09 Apr 220009h02m50s19°47'N9.7”0.0
23 Apr 220009h15m10s18°23'N8.6”0.3

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 08h57m50s 20°44'N Cancer -0.3 11.1"

The coordinates above are given in J2000.0.

The sky on 2 Mar 2026

The sky on 2 March 2026
Sunrise
06:17
Sunset
17:48
Twilight ends
19:12
Twilight begins
04:54


Waxing Gibbous

99%

14 days old

Planets
Rise Culm. Set
Mercury 06:28 12:29 18:30
Venus 06:59 12:53 18:48
Moon 17:22 23:55 06:18
Mars 05:50 11:19 16:47
Jupiter 13:03 20:12 03:22
Saturn 07:19 13:18 19:17
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

24 Mar 2200  –  Mars ends retrograde motion
06 Feb 2202  –  Mars enters retrograde motion
18 Mar 2202  –  Mars at opposition
21 Mar 2202  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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