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.

2052 apparition of Mars

22 Sep 2052 – Mars enters retrograde motion
20 Oct 2052 – Mars at perigee
28 Oct 2052 – Mars at opposition
29 Nov 2052 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2052 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 01h45m10s 11°12'N Pisces -1.5 16.3"

The coordinates above are given in J2000.0.

From Cambridge , it will be visible in the evening sky, becoming accessible around 16:30 (EDT), 25° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:51, 58° above your southern horizon. It will continue to be observable until around 02:48, when it sinks below 7° 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 panels below show the month-by-month change in Mars' apparent size in coming weeks, as it recedes from the Earth:

04 Oct 2052
01 Nov 2052
29 Nov 2052
27 Dec 2052
24 Jan 2053

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

Date Angular size Mag
20 Sep 205218.6”-1.8
04 Oct 205220.3”-2.1
18 Oct 205221.2”-2.4
01 Nov 205220.7”-2.4
15 Nov 205218.8”-2.0
29 Nov 205216.3”-1.5
13 Dec 205214.0”-1.0
27 Dec 205211.9”-0.6
10 Jan 205310.3”-0.2
24 Jan 20539.0”0.1
07 Feb 20537.9”0.4

The sky on 3 Jul 2024

The sky on 3 July 2024
Sunrise
05:09
Sunset
20:24
Twilight ends
22:37
Twilight begins
02:56


Waning Crescent

3%

27 days old

Planets
Rise Culm. Set
Mercury 06:44 14:12 21:39
Venus 05:47 13:21 20:56
Moon 02:34 10:37 18:50
Mars 01:52 08:57 16:02
Jupiter 02:57 10:23 17:48
Saturn 23:39 05:19 11:00
All times shown in EDT.

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

29 Nov 2052  –  Mars ends retrograde motion
08 Nov 2054  –  Mars enters retrograde motion
11 Dec 2054  –  Mars at perigee
17 Dec 2054  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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