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.

2244–2245 apparition of Mars

23 Nov 2244 – Mars enters retrograde motion
27 Dec 2244 – Mars at perigee
02 Jan 2245 – Mars at opposition
08 Feb 2245 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2244–2245 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 05h59m10s 26°58'N Taurus -0.6 12.0"

The coordinates above are given in J2000.0.

From Columbus , it will be visible in the evening sky, becoming accessible around 18:04 (EDT), 48° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:14, 77° above your southern horizon. It will continue to be observable until around 04:01, when it sinks below 8° 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:

14 Dec 2244
11 Jan 2245
08 Feb 2245
08 Mar 2245
05 Apr 2245

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

Date Angular size Mag
30 Nov 224413.9”-1.0
14 Dec 224415.1”-1.3
28 Dec 224415.6”-1.6
11 Jan 224515.0”-1.4
25 Jan 224513.6”-1.0
08 Feb 224512.0”-0.6
22 Feb 224510.4”-0.2
08 Mar 22459.1”0.2
22 Mar 22458.1”0.5
05 Apr 22457.2”0.7
19 Apr 22456.5”1.0

The sky on 1 Oct 2024

The sky on 1 October 2024
Sunrise
07:26
Sunset
19:13
Twilight ends
20:43
Twilight begins
05:55


Waning Crescent

0%

28 days old

Planets
Rise Culm. Set
Mercury 07:29 13:24 19:18
Venus 10:07 15:18 20:29
Moon 06:15 12:37 18:50
Mars 00:26 07:53 15:21
Jupiter 22:45 06:10 13:34
Saturn 18:16 23:50 05:25
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

08 Feb 2245  –  Mars ends retrograde motion
29 Dec 2246  –  Mars enters retrograde motion
06 Feb 2247  –  Mars at perigee
07 Feb 2247  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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