Mars ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

1995 apparition of Mars

02 Jan 1995 – Mars enters retrograde motion
11 Feb 1995 – Mars at perigee
11 Feb 1995 – Mars at opposition
24 Mar 1995 – Mars ends retrograde motion

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.

The panels below show the month-by-month change in Mars' apparent size in coming weeks, as it recedes from the Earth:

17 Dec 1994
9.8"
14 Jan 1995
12.4"
11 Feb 1995
13.9"
11 Mar 1995
12.3"
08 Apr 1995
9.7"

Observing Mars

Mars leaves retrograde motion as its 1995 apparition comes to an end, although it will remain visible for some weeks in the dusk sky.

As retrograde motion ends, it will be visible in the evening sky, becoming accessible around 18:30 (PST), 55° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:50, 76° above your southern horizon. It will continue to be observable until around 02:58, 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 table below lists Mars' angular size and brightness at two-week intervals throughout its apparition:

Date Right ascension Declination Angular size Magnitude
03 Dec 199410h03m20s14°33'N8.8”0.2
17 Dec 199410h17m20s13°47'N9.8”-0.0
31 Dec 199410h23m50s13°44'N11.1”-0.4
14 Jan 199510h20m50s14°34'N12.4”-0.7
28 Jan 199510h07m50s16°12'N13.5”-1.0
11 Feb 199509h47m30s18°08'N13.9”-1.2
25 Feb 199509h26m10s19°39'N13.4”-1.0
11 Mar 199509h11m30s20°17'N12.3”-0.7
25 Mar 199509h06m50s20°03'N11.0”-0.3
08 Apr 199509h11m40s19°09'N9.7”0.0
22 Apr 199509h23m50s17°44'N8.7”0.3

As it leaves retrograde motion, its celestial coordinates will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 09h06m50s 20°06'N Cancer -0.3 11.1"

The coordinates above are given in J2000.0.

The sky on 31 Jan 2026

The sky on 31 January 2026
Sunrise
06:47
Sunset
17:20
Twilight ends
18:46
Twilight begins
05:21


Waxing Gibbous

99%

13 days old

Planets
Rise Culm. Set
Mercury 07:20 12:35 17:50
Venus 07:14 12:29 17:45
Moon 16:14 23:34 06:45
Mars 06:36 11:43 16:50
Jupiter 15:11 22:20 05:28
Saturn 09:09 15:04 21:00
All times shown in PST.

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

24 Mar 1995  –  Mars ends retrograde motion
05 Feb 1997  –  Mars enters retrograde motion
16 Mar 1997  –  Mars at opposition
20 Mar 1997  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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