Setting course for the stars at the Meudon Observatory for Heritage Days 2026.

The European Heritage Days resume their orbit on September 19 and 20, 2026, with a program that once again promises to lift the gaze toward the treasures of Paris and the Île-de-France region. Over an entire weekend, monuments, institutions, scientific sites and other places typically closed to the public open their doors through free tours, demonstrations and one‑of‑a‑kind encounters. It’s an opportunity to change perspective, to step through doors rarely opened, and to discover venues where history, culture and research intersect. Once again this year, the Observatoire de Paris, Meudon site is among the must‑visit stops.

Heritage Days 2026 in the 92: discover the hidden treasures of Hauts-de-Seine
Heritage Days in Hauts-de-Seine (92) offer a unique chance to uncover the department’s historical and cultural treasures. From September 19 to 20, 2026, you can even visit sites usually closed to the public, from Montrouge to Saint-Cloud. Here’s the program. [Read more]

Perched on the heights of the city of Hauts-de-Seine (92), the Observatoire de Paris, site de Meudon will welcome visitors during this heritage weekend, exclusively by reservation required on Saturday, September 19. Reservations will open on Wednesday, August 26 at 2:00 PM. Located in the Meudon château estate since the late 19th century, this historic site of the Observatoire de Paris-PSL is one of the premier centers of French astronomy. Here you can discover notably the Grande Coupole, which houses one of the largest astronomical telescopes in the world, as well as a cluster of buildings dedicated to observing the Sun, the planets and the stars for more than a century. Needless to say, spots are likely to disappear at the speed of light...

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• The week's best deals from September 7 to 13, 2026 in Paris and Île-de-France

Heritage Days 2026 program at the Paris Observatory, Meudon site:

• Guided tour of the Paris Observatory — Meudon site

  Accompanied by one of its scientists, stroll through the old royal hunting grounds and tour the cradle of French astrophysics: Europe’s largest astronomical telescope housed in its monumental dome, and the spectroheliograph, a device long used to monitor solar activity—a tradition that has endured for more than a century.

  Participation conditions: Free | Booking required - https://www.billetweb.fr/journees-du-patrimoine-2026-observatoire-de-paris-site-de-meudon

  Hours : Saturday, September 19, 2026 — 12:00 PM to 5:00 PM