Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

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.

2261–2262 apparition of Mars

15 Dec 2261 – Mars enters retrograde motion
21 Jan 2262 – Mars at perigee
24 Jan 2262 – Mars at opposition
05 Mar 2262 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2261–2262 apparition comes to an end, although it will remain visible for some weeks in the dusk sky.

Its celestial coordinates as it leaves retrograde motion will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 07h37m50s 25°14'N Gemini -0.4 11.3"

The coordinates above are given in J2000.0.

From South El Monte , it will be visible in the evening sky, becoming accessible around 17:56 (PDT), 54° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:34, 81° above your southern horizon. It will continue to be observable until around 02:59, 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 panels below show the month-by-month change in Mars' apparent size in coming weeks, as it recedes from the Earth:

08 Jan 2262
05 Feb 2262
05 Mar 2262
02 Apr 2262
30 Apr 2262

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

Date Angular size Mag
25 Dec 226112.9”-0.8
08 Jan 226214.0”-1.1
22 Jan 226214.4”-1.3
05 Feb 226213.9”-1.1
19 Feb 226212.7”-0.8
05 Mar 226211.3”-0.4
19 Mar 22629.9”-0.0
02 Apr 22628.8”0.3
16 Apr 22627.8”0.6
30 Apr 22627.0”0.8
14 May 22626.4”1.0

The sky on 23 May 2025

The sky on 23 May 2025
Sunrise
05:42
Sunset
19:52
Twilight ends
21:32
Twilight begins
04:03


Waning Crescent

8%

26 days old

Planets
Rise Culm. Set
Mercury 05:21 12:16 19:11
Venus 03:34 09:50 16:07
Moon 03:12 09:35 16:08
Mars 11:10 18:02 00:53
Jupiter 07:16 14:27 21:37
Saturn 02:50 08:47 14:44
All times shown in PDT.

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

05 Mar 2262  –  Mars ends retrograde motion
19 Jan 2264  –  Mars enters retrograde motion
28 Feb 2264  –  Mars at opposition
29 Feb 2264  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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