Celestia Forums

On September 11th in 1170, Mars was observed to transit Jupiter by Gervase of Canterbury.

Here's Celestia's view of that event, shortly after first contact
(this is a link to a high resolution image.)

The viewpoint is from over England.

you have been having fun with transits

? - how many can you find

me i have no idia how many there are

There are 190 events like these (planets occultation/transit by another planet as seen from earth) from 3000BC to 3000AD.
The next one is in Nov 22, 2065 and Venus will transit onto Jupiter. There is a chance to see it in our life time. The last one occured in 1818.

People have been generating lists of transits for a while. The author of Guide seems to have done a rather thorough investigation. See
http://www.projectpluto.com/interest.htm
and
http://www.projectpluto.com/mut_pln.htm#mutual_planetary

Personally, I think Celestia makes much better looking renditions of the events although its timing is off somewhat due to the lack of light delay.