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.

2283 apparition of Mars

21 Mar 2283 – Mars enters retrograde motion
27 Apr 2283 – Mars at opposition
04 May 2283 – Mars at perigee
07 Jun 2283 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 2283 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 13h26m20s 9°28'S Virgo -0.9 13.8"

The coordinates above are given in J2000.0.

From Fairfield , it will be visible in the evening sky, becoming accessible around 20:27 (EDT), 38° above your southern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:14, 39° above your southern horizon. It will continue to be observable until around 01:55, 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:

12 Apr 2283
10 May 2283
07 Jun 2283
05 Jul 2283
02 Aug 2283

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

Date Angular size Mag
29 Mar 228313.2”-0.9
12 Apr 228314.8”-1.3
26 Apr 228315.9”-1.6
10 May 228315.9”-1.5
24 May 228315.1”-1.3
07 Jun 228313.8”-0.9
21 Jun 228312.5”-0.7
05 Jul 228311.2”-0.4
19 Jul 228310.2”-0.2
02 Aug 22839.3”0.0
16 Aug 22838.6”0.2

The sky on 3 Oct 2024

The sky on 3 October 2024
Sunrise
06:49
Sunset
18:30
Twilight ends
20:02
Twilight begins
05:17


Waxing Crescent

1%

1 day old

Planets
Rise Culm. Set
Mercury 07:01 12:49 18:38
Venus 09:35 14:40 19:46
Moon 07:34 13:15 18:47
Mars 23:40 07:11 14:42
Jupiter 21:55 05:23 12:51
Saturn 17:30 23:03 04:37
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

07 Jun 2283  –  Mars ends retrograde motion
13 May 2285  –  Mars enters retrograde motion
15 Jun 2285  –  Mars at opposition
23 Jun 2285  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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