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.

1962–1963 apparition of Mars

26 Dec 1962 – Mars enters retrograde motion
02 Feb 1963 – Mars at perigee
04 Feb 1963 – Mars at opposition
16 Mar 1963 – Mars ends retrograde motion

Observing Mars

Mars leaves retrograde motion as its 1962–1963 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 08h36m40s 22°15'N Cancer -0.3 11.1"

The coordinates above are given in J2000.0.

From Cambridge , it will be visible in the evening sky, becoming accessible around 18:19 (EST), 53° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:45, 69° above your southern horizon. It will continue to be observable until around 03:16, when it sinks below 9° 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:

19 Jan 1963
16 Feb 1963
16 Mar 1963
13 Apr 1963
11 May 1963

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

Date Angular size Mag
05 Jan 196312.4”-0.7
19 Jan 196313.5”-1.0
02 Feb 196314.0”-1.2
16 Feb 196313.6”-1.1
02 Mar 196312.5”-0.7
16 Mar 196311.1”-0.3
30 Mar 19639.8”-0.0
13 Apr 19638.7”0.3
27 Apr 19637.8”0.6
11 May 19637.1”0.8
25 May 19636.5”1.0

The sky on 23 Nov 2024

The sky on 23 November 2024
Sunrise
06:43
Sunset
16:15
Twilight ends
17:54
Twilight begins
05:03


Waning Crescent

40%

22 days old

Planets
Rise Culm. Set
Mercury 08:33 12:55 17:17
Venus 10:09 14:32 18:54
Moon 23:09 06:06 12:50
Mars 20:36 04:03 11:30
Jupiter 17:09 00:40 08:11
Saturn 12:58 18:29 23:59
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

16 Mar 1963  –  Mars ends retrograde motion
28 Jan 1965  –  Mars enters retrograde motion
09 Mar 1965  –  Mars at opposition
11 Mar 1965  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

Share