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.

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

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.

Its celestial coordinates as it leaves retrograde motion 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.

From Fairfield , it will be visible in the evening sky, becoming accessible around 17:59 (EST), 51° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:50, 74° above your southern horizon. It will continue to be observable until around 03:34, 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:

29 Dec 2024
26 Jan 2025
23 Feb 2025
23 Mar 2025
20 Apr 2025

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

Date Angular size Mag
15 Dec 202413.0”-0.8
29 Dec 202414.2”-1.2
12 Jan 202514.6”-1.4
26 Jan 202514.1”-1.2
09 Feb 202512.8”-0.8
23 Feb 202511.4”-0.4
09 Mar 202510.0”-0.1
23 Mar 20258.8”0.3
06 Apr 20257.8”0.6
20 Apr 20257.0”0.8
04 May 20256.4”1.0

The sky on 23 Feb 2025

The sky on 23 February 2025
Sunrise
06:34
Sunset
17:36
Twilight ends
19:08
Twilight begins
05:02


Waning Crescent

14%

25 days old

Planets
Rise Culm. Set
Mercury 07:07 12:49 18:31
Venus 07:28 14:03 20:39
Moon 04:01 08:10 12:21
Mars 13:05 20:50 04:35
Jupiter 10:51 18:16 01:42
Saturn 07:20 13:02 18:45
All times shown in EST.

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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