Monday, May 9, 2016, from 1:12 p.m. to 8:40 p.m. (local time), Mercury will transit in front of the Sun. It is a relatively rare event, especially if visible in its entirety, from beginning to end. The next transit of Mercury will take place in 2019, and the next to be visible in France in full will be held in 2039.
The IAS hosts on that occasion observations and presentations for laboratory staff, and the Orsay/Gif campus personnel.
From 1pm to 6pm :