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.

2116 apparition of Mars

16 Oct 2116 – Mars enters retrograde motion
14 Nov 2116 – Mars at perigee
22 Nov 2116 – Mars at opposition
27 Dec 2116 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2116 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 03h16m00s 20°14'N Aries -1.1 14.2"

The coordinates above are given in J2000.0.

From Fairfield , it will be visible in the evening sky, becoming accessible around 16:43 (EST), 35° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:42, 69° above your southern horizon. It will continue to be observable until around 03:10, 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:

01 Nov 2116
29 Nov 2116
27 Dec 2116
24 Jan 2117
21 Feb 2117

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

Date Angular size Mag
18 Oct 211616.7”-1.5
01 Nov 211618.2”-1.8
15 Nov 211618.8”-2.1
29 Nov 211618.1”-2.0
13 Dec 211616.4”-1.6
27 Dec 211614.2”-1.1
10 Jan 211712.2”-0.6
24 Jan 211710.5”-0.2
07 Feb 21179.2”0.1
21 Feb 21178.1”0.4
07 Mar 21177.2”0.7

The sky on 24 Nov 2024

The sky on 24 November 2024
Sunrise
06:49
Sunset
16:27
Twilight ends
18:04
Twilight begins
05:12


Waning Crescent

31%

23 days old

Planets
Rise Culm. Set
Mercury 08:34 13:01 17:28
Venus 10:14 14:42 19:09
Moon 00:22 06:55 13:17
Mars 20:46 04:08 11:31
Jupiter 17:18 00:45 08:11
Saturn 13:01 18:33 00:05
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

27 Dec 2116  –  Mars ends retrograde motion
26 Nov 2118  –  Mars enters retrograde motion
31 Dec 2118  –  Mars at perigee
05 Jan 2119  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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