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.

2293–2294 apparition of Mars

23 Dec 2293 – Mars enters retrograde motion
30 Jan 2294 – Mars at perigee
01 Feb 2294 – Mars at opposition
13 Mar 2294 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2293–2294 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 08h10m30s 23°44'N Cancer -0.4 11.2"

The coordinates above are given in J2000.0.

From Cambridge , it will be visible in the evening sky, becoming accessible around 18:52 (EDT), 52° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:27, 71° above your southern horizon. It will continue to be observable until around 04:05, 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:

16 Jan 2294
13 Feb 2294
13 Mar 2294
10 Apr 2294
08 May 2294

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

Date Angular size Mag
02 Jan 229412.6”-0.7
16 Jan 229413.7”-1.1
30 Jan 229414.1”-1.3
13 Feb 229413.7”-1.1
27 Feb 229412.6”-0.7
13 Mar 229411.2”-0.4
27 Mar 22949.9”-0.0
10 Apr 22948.7”0.3
24 Apr 22947.8”0.6
08 May 22947.0”0.8
22 May 22946.4”1.0

The sky on 4 Oct 2024

The sky on 4 October 2024
Sunrise
06:42
Sunset
18:19
Twilight ends
19:53
Twilight begins
05:08


Waxing Crescent

3%

2 days old

Planets
Rise Culm. Set
Mercury 06:58 12:43 18:29
Venus 09:32 14:33 19:34
Moon 08:29 13:47 18:57
Mars 23:26 07:01 14:36
Jupiter 21:39 05:11 12:43
Saturn 17:18 22:50 04:23
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

13 Mar 2294  –  Mars ends retrograde motion
27 Jan 2296  –  Mars enters retrograde motion
06 Mar 2296  –  Mars at opposition
08 Mar 2296  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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