Mars enters retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

Mars will enter retrograde motion, halting its usual eastward movement through the constellations, and turning to move westwards instead. This reversal of direction is a phenomenon that all the solar system's outer planets periodically undergo, a few months before they reach 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.

2076 apparition of Mars

08 Feb 2076 – Mars enters retrograde motion
19 Mar 2076 – Mars at opposition
22 Mar 2076 – Mars at perigee
29 Apr 2076 – Mars ends retrograde motion

Observing Mars

Mars enters retrograde motion as its 2076 apparition gets underway, although it has already been visible for some weeks in the pre-dawn sky.

Its celestial coordinates as it enters retrograde motion will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 12h33m30s 0°04'N Virgo -0.4 11.1"

The coordinates above are given in J2000.0.

From Fairfield , it will be visible in the morning sky, becoming accessible around 22:02, when it reaches an altitude of 9° above your eastern horizon. It will then reach its highest point in the sky at 03:13, 48° above your southern horizon. It will be lost to dawn twilight around 06:28, 29° above your south-western horizon.

Over the following weeks, Mars will reach its highest point in the sky four minutes earlier each night, gradually becoming visible in the evening sky, as well as the pre-dawn sky, as it approaches opposition.

The panels below show the month-by-month change in Mars' apparent size in coming weeks:

14 Dec 2075
11 Jan 2076
08 Feb 2076
07 Mar 2076
04 Apr 2076

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

Date Angular size Mag
30 Nov 20756.3”1.0
14 Dec 20756.9”0.8
28 Dec 20757.7”0.6
11 Jan 20768.6”0.3
25 Jan 20769.8”-0.0
08 Feb 207611.1”-0.4
22 Feb 207612.6”-0.7
07 Mar 207613.7”-1.1
21 Mar 207614.2”-1.3
04 Apr 207613.9”-1.1
18 Apr 207612.8”-0.8

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

45%

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

08 Feb 2076  –  Mars enters retrograde motion
19 Mar 2076  –  Mars at opposition
22 Mar 2076  –  Mars at perigee
29 Apr 2076  –  Mars ends retrograde motion

Image credit

© NASA/Hubble Space Telescope

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