Astronomical Transit - Mutual Planetary Transits and Occultations

Mutual Planetary Transits and Occultations

In rare cases, one planet can transit in front of another. The next time this will happen (as seen from Earth) will be on 22 November 2065 at about 12:43 UTC, when Venus near superior conjunction (with an angular diameter of 10.6") will transit in front of Jupiter (with an angular diameter of 30.9"); however, this will take place only 8° west of the Sun, and will therefore not be visible to the unaided/unprotected eye. When the nearer object has a larger angular diameter than the farther object, thus covering it completely, the event is not a transit but an occultation. Before transiting Jupiter, Venus will occult Jupiter's moon Ganymede at around 11:24 UTC as seen from some southernmost parts of Earth. Parallax will cause actual observed times to vary by a few minutes, depending on the precise location of the observer.

There are only 18 mutual planetary transits and occultations as seen from Earth between 1700 and 2200. Note the long break of events between 1818 and 2065.

• 19 Sep 1702 – Jupiter occults Neptune
• 20 Jul 1705 – Mercury transits Jupiter
• 14 Jul 1708 – Mercury occults Uranus
• 4 Oct 1708 – Mercury transits Jupiter
• 28 May 1737 – Venus occults Mercury
• 29 Aug 1771 – Venus transits Saturn
• 21 Jul 1793 – Mercury occults Uranus
• 9 Dec 1808 – Mercury transits Saturn
• 3 Jan 1818 – Venus transits Jupiter
• 22 Nov 2065 – Venus transits Jupiter
• 15 Jul 2067 – Mercury occults Neptune
• 11 Aug 2079 – Mercury occults Mars
• 27 Oct 2088 – Mercury transits Jupiter
• 7 Apr 2094 – Mercury transits Jupiter
• 21 Aug 2104 – Venus occults Neptune
• 14 Sep 2123 – Venus transits Jupiter
• 29 Jul 2126 – Mercury occults Mars
• 3 Dec 2133 – Venus occults Mercury

Occultations after 2200 include:

• 1 Dec 40396 TT – Uranus transits Neptune

The 1737 event was observed by John Bevis at Greenwich Observatory – it is the only detailed account of a mutual planetary occultation. A transit of Mars across Jupiter on 12 Sep 1170 was observed by the monk Gervase at Canterbury, and by Chinese astronomers. In addition, an occultation of Mars by Venus was observed by Michael Maestlin at Heidelberg on 3 October 1590.

Future transits that can be seen from planets other than Earth include:

• 23 Jun 2021 – Earth occults Pluto as seen from Venus
• 29 Nov 2022 – Earth occults Mercury as seen from Mars
• 12 Jan 2032 – Earth transits Saturn as seen from Venus (south pole)
• 11 Sep 2032 – Mercury transits Jupiter as seen from Mars
• 2 Sep 2064 – Venus occults Uranus as seen from Mercury
• 22 Nov 2065 – Venus occults Earth as seen from Jupiter
• 11 Aug 2079 – Mercury transits Earth as seen from Mars
• 4 Nov 2079 – Jupiter occults Uranus as seen from Mars
• 27 Oct 2088 – Mercury transits Earth as seen from Jupiter
• 7 Apr 2094 – Mercury transits Earth as seen from Jupiter
• 20 Apr 2100 – Venus transits Saturn as seen from Mercury