Saturday, September 19 : in Meudon
This year we are celebrating the 150th anniversary of the founding of the Meudon Astrophysics Observatory and the 100th anniversary of its affiliation with the Observatoire de Paris. It is the cradle of French astrophysics, founded on the initiative of astronomer Jules Janssen (1824–1907). Today, the site plays a major role in the field.
The tour will allow you to enjoy the grounds—a former royal hunting estate—and to see its most iconic observational instruments :
- the spectroheliograph, which has been used to monitor solar activity daily for over a century ;
- and Europe’s largest astronomical telescope, which was recently restored.
Sunday, September 20 : in Paris
Founded in 1667 during the reign of Louis XIV, the Observatory is one of the world’s oldest astronomical observatories still in operation. This unique site embodies 360 years of astronomical research and exploration of the universe.
This is a rare opportunity to step inside its extraordinary historic building, designed by Claude Perrault (1613–1688), the brother of the storyteller, and to discover the precious legacy it preserves : antique telescopes, celestial globes, astronomical clocks, and many other fascinating instruments.
Highlights include :
• the Council Chamber and its painted ceiling,
• the Grand Gallery,
• the Paris Meridian Room,
• the rooftop terrace with a panoramic view of Paris,
• the Arago Dome and its large astronomical telescope from 1854.
| Free tours (in French), by reservation only : Reservations open on Wednesday, August 26, at 2:00 p.m. :
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These are events not to be missed for anyone who wants to understand today’s world through the lens of science. Because now more than ever, scientific literacy is an essential tool for becoming an informed citizen.

