Jupiter enters retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Jupiter

Jupiter 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 a planet in the outer solar system. Not drawn to scale.

1995 apparition of Jupiter

01 Apr 1995 – Jupiter enters retrograde motion
01 Jun 1995 – Jupiter at opposition
02 Jun 1995 – Jupiter at perigee
02 Aug 1995 – Jupiter ends retrograde motion

Observing Jupiter

Jupiter enters retrograde motion as its 1995 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
Jupiter 16h57m10s 21°49'S Ophiuchus -2.3 39.8"

The coordinates above are given in J2000.0.

From Los Angeles , it will be visible in the morning sky, becoming accessible around 00:00, when it reaches an altitude of 7° above your south-eastern horizon. It will then reach its highest point in the sky at 04:12, 34° above your southern horizon. It will be lost to dawn twilight around 05:24, 31° above your southern horizon.

Over the following weeks, Jupiter 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 sky on 22 Nov 2024

The sky on 22 November 2024
Sunrise
06:30
Sunset
16:45
Twilight ends
18:12
Twilight begins
05:02


Waning Crescent

48%

21 days old

Planets
Rise Culm. Set
Mercury 08:17 13:06 17:54
Venus 09:50 14:39 19:28
Moon 22:39 05:37 12:27
Mars 21:10 04:14 11:18
Jupiter 17:46 00:53 08:00
Saturn 13:02 18:40 00:19
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

01 Apr 1995  –  Jupiter enters retrograde motion
01 Jun 1995  –  Jupiter at opposition
02 Aug 1995  –  Jupiter ends retrograde motion
04 May 1996  –  Jupiter enters retrograde motion

Image credit

© NASA/Cassini

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