Saturn ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed


Objects: Saturn

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

2170 apparition of Saturn

16 Jun 2170 – Saturn enters retrograde motion
26 Aug 2170 – Saturn at opposition
03 Nov 2170 – Saturn ends retrograde motion

Observing Saturn

Saturn leaves retrograde motion as its 2170 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
Saturn 22h01m00s 13°54'S Aquarius 0.5 17.7"

The coordinates above are given in J2000.0.

From Columbus , it will be visible in the evening sky, becoming accessible around 18:54 (EDT), 30° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:39, 36° above your southern horizon. It will continue to be observable until around 00:48, when it sinks below 10° above your south-western horizon.

Over the following weeks, Saturn will reach its highest point in the sky four minutes earlier each night, gradually disappearing into evening twilight.

The sky on 30 Apr 2024

The sky on 30 April 2024
Sunrise
06:30
Sunset
20:25
Twilight ends
22:09
Twilight begins
04:47


Waning Crescent

49%

22 days old

Planets
Rise Culm. Set
Mercury 05:42 12:00 18:18
Venus 06:13 12:53 19:32
Moon 02:24 06:57 11:35
Mars 04:57 10:56 16:55
Jupiter 07:15 14:21 21:27
Saturn 04:28 10:08 15:47
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

03 Nov 2170  –  Saturn ends retrograde motion
29 Jun 2171  –  Saturn enters retrograde motion
07 Sep 2171  –  Saturn at opposition
15 Nov 2171  –  Saturn ends retrograde motion

Image credit

© NASA/Cassini

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