Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2024–2025 apparition of Mars

06 Dec 2024 – Mars enters retrograde motion
12 Jan 2025 – Mars at perigee
15 Jan 2025 – Mars at opposition
23 Feb 2025 – 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:

20 Nov 2024
10.7"
18 Dec 2024
13.3"
15 Jan 2025
14.6"
12 Feb 2025
12.5"
12 Mar 2025
9.7"

Observing Mars

Mars leaves retrograde motion as its 2024–2025 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 18:04 (PST), 53° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:49, 82° above your southern horizon. It will continue to be observable until around 03:15, 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 table below lists Mars' angular size and brightness at two-week intervals throughout its apparition:

Date Right ascension Declination Angular size Magnitude
06 Nov 202408h12m40s21°34'N9.6”-0.0
20 Nov 202408h28m20s21°15'N10.7”-0.3
04 Dec 202408h35m30s21°28'N12.0”-0.6
18 Dec 202408h32m00s22°20'N13.3”-0.9
01 Jan 202508h17m30s23°44'N14.3”-1.2
15 Jan 202507h54m50s25°10'N14.6”-1.4
29 Jan 202507h32m20s26°04'N13.9”-1.1
12 Feb 202507h17m50s26°16'N12.5”-0.7
26 Feb 202507h14m20s25°57'N11.1”-0.3
12 Mar 202507h21m10s25°20'N9.7”0.0
26 Mar 202507h35m50s24°26'N8.6”0.3

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

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 07h14m10s 26°03'N Gemini -0.4 11.4"

The coordinates above are given in J2000.0.

The sky on 23 Feb 2025

The sky on 23 February 2025
Sunrise
06:25
Sunset
17:42
Twilight ends
19:06
Twilight begins
05:02


Waning Crescent

14%

26 days old

Planets
Rise Culm. Set
Mercury 07:02 12:49 18:35
Venus 07:34 14:02 20:30
Moon 03:37 08:17 12:57
Mars 13:28 20:49 04:09
Jupiter 11:09 18:15 01:21
Saturn 07:14 13:01 18:48
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

23 Feb 2025  –  Mars ends retrograde motion
10 Jan 2027  –  Mars enters retrograde motion
19 Feb 2027  –  Mars at opposition
19 Feb 2027  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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