Planetary transits and occultations

An occultation of Mars by Venus on 13 October 1590 was observed by the German astronomer Michael Maestlin at Heidelberg.[2][3] The 1737 event (see list below) 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 September 1170 was observed by the monk Gervase at Canterbury,[4] and by Chinese astronomers.[5]

The next time a mutual planetary transit or occultation 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. 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. There is a very long break of events between 1818 and 2065.[3]

• 19 September 1702 – Jupiter occults Neptune (pre-discovery)
• 20 July 1705 – Mercury transits Jupiter
• 14 July 1708 – Mercury occults Uranus (pre-discovery)

A simulation of Venus transiting Jupiter, as it did on 3rd of January, 1818.

• 4 October 1708 – Mercury transits Jupiter
• 28 May 1737 – Venus occults Mercury
• 29 August 1771 – Venus transits Saturn
• 21 July 1793 – Mercury occults Uranus
• 9 December 1808 – Mercury transits Saturn
• 3 January 1818 – Venus transits Jupiter
• 22 November 2065 – Venus transits Jupiter
• 15 July 2067 – Mercury occults Neptune
• 11 August 2079 – Mercury occults Mars
• 27 October 2088 – Mercury transits Jupiter
• 7 April 2094 – Mercury transits Jupiter
• 21 August 2104 – Venus occults Neptune
• 14 September 2123 – Venus transits Jupiter
• 29 July 2126 – Mercury occults Mars
• 3 December 2133 – Venus occults Mercury

Twice during the orbital cycles of Jupiter and Saturn, the equatorial (and satellite) planes of those planets are aligned with Earth's orbital plane, resulting in a series of mutual occultations and eclipses between the moons of these giant planets. The terms eclipse, occultation, and transit are also used to describe these events.[1] A satellite of Jupiter (for example) may be eclipsed (i.e. made dimmer because it moves into Jupiter's shadow), occulted (i.e. hidden from view because Jupiter lies on our line of sight), or may transit (i.e. pass in front of) Jupiter's disk (see also Solar eclipses on Jupiter).