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.

2061 apparition of Mars

22 Feb 2061 – Mars enters retrograde motion
02 Apr 2061 – Mars at opposition
07 Apr 2061 – Mars at perigee
13 May 2061 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2061 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 12h10m50s 0°06'N Virgo -0.7 12.5"

The coordinates above are given in J2000.0.

From Columbus , it will be visible in the evening sky, becoming accessible around 20:58 (EDT), 46° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 22:13, 50° above your southern horizon. It will continue to be observable until around 03:28, when it sinks below 8° 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:

18 Mar 2061
15 Apr 2061
13 May 2061
10 Jun 2061
08 Jul 2061

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

Date Angular size Mag
04 Mar 206112.5”-0.7
18 Mar 206113.9”-1.1
01 Apr 206114.7”-1.4
15 Apr 206114.7”-1.3
29 Apr 206113.8”-1.0
13 May 206112.5”-0.7
27 May 206111.3”-0.4
10 Jun 206110.1”-0.1
24 Jun 20619.2”0.1
08 Jul 20618.4”0.3
22 Jul 20617.7”0.5

The sky on 28 Apr 2024

The sky on 28 April 2024
Sunrise
06:33
Sunset
20:23
Twilight ends
22:06
Twilight begins
04:50


Waning Gibbous

74%

20 days old

Planets
Rise Culm. Set
Mercury 05:47 12:05 18:23
Venus 06:15 12:51 19:28
Moon 00:38 05:01 09:22
Mars 05:02 10:58 16:55
Jupiter 07:21 14:27 21:33
Saturn 04:36 10:15 15:54
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 May 2061  –  Mars ends retrograde motion
09 Apr 2063  –  Mars enters retrograde motion
14 May 2063  –  Mars at opposition
22 May 2063  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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