© NASA/Cassini

Saturn ends retrograde motion

Dominic Ford, Editor
From the Outer Planets feed

Objects: Saturn
Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
The sky at

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.

1980 apparition of Saturn

06 Jan 1980 – Saturn enters retrograde motion
02 Mar 1980 – Equinox on Saturn
12 Mar 1980 – Saturn ring plane crossing
13 Mar 1980 – Saturn at opposition
22 May 1980 – Saturn ends retrograde motion

Observing Saturn

Saturn leaves retrograde motion as its 1980 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 11h28m30s 5°53'N Leo 0.7 18.3"

The coordinates above are given in J2000.0.

From Ashburn , it will become visible around 21:00 (EST), 56° above your southern horizon, as dusk fades to darkness. It will then sink towards the horizon, setting at 02:55.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

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 28 November 2021
Sunrise
07:07
Sunset
16:51
Twilight ends
18:23
Twilight begins
05:31

24-day old moon
Waning Crescent

29%

24 days old

Planets
Rise Culm. Set
Mercury 07:09 11:56 16:43
Venus 10:28 15:02 19:35
Moon 00:16 07:03 13:42
Mars 05:44 10:48 15:52
Jupiter 12:15 17:31 22:46
Saturn 11:26 16:25 21:23
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

13 Mar 1980  –  Saturn at opposition
23 Jul 1980  –  Saturn ring plane crossing
26 Mar 1981  –  Saturn at opposition
08 Apr 1982  –  Saturn at opposition

Image credit

© NASA/Cassini

Share

Follow

Ashburn

Latitude:
Longitude:
Timezone:

39.04°N
77.49°W
EST

Color scheme