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.

2080 apparition of Mars

14 May 2080 – Mars enters retrograde motion
16 Jun 2080 – Mars at opposition
24 Jun 2080 – Mars at perigee
22 Jul 2080 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2080 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 17h05m50s 27°19'S Ophiuchus -1.8 18.8"

The coordinates above are given in J2000.0.

From Fairfield , it will be visible in the evening sky, becoming accessible around 20:35 (EST), 19° above your southern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:51, 21° above your southern horizon. It will continue to be observable until around 01:06, when it sinks below 7° above your south-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:

27 May 2080
24 Jun 2080
22 Jul 2080
19 Aug 2080
16 Sep 2080

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

Date Angular size Mag
13 May 208016.1”-1.4
27 May 208018.4”-1.9
10 Jun 208020.3”-2.3
24 Jun 208021.1”-2.3
08 Jul 208020.4”-2.1
22 Jul 208018.9”-1.8
05 Aug 208017.0”-1.5
19 Aug 208015.2”-1.2
02 Sep 208013.6”-0.9
16 Sep 208012.2”-0.7
30 Sep 208011.0”-0.4

The sky on 22 Nov 2024

The sky on 22 November 2024
Sunrise
06:47
Sunset
16:28
Twilight ends
18:05
Twilight begins
05:10


Waning Crescent

44%

21 days old

Planets
Rise Culm. Set
Mercury 08:40 13:06 17:32
Venus 10:13 14:39 19:06
Moon 22:16 05:32 12:36
Mars 20:52 04:15 11:38
Jupiter 17:26 00:53 08:20
Saturn 13:09 18:41 00:13
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

22 Jul 2080  –  Mars ends retrograde motion
02 Aug 2082  –  Mars enters retrograde motion
30 Aug 2082  –  Mars at perigee
01 Sep 2082  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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