The Observatory Terrace
The best free view of Paris in the western suburbs — and almost nobody outside Meudon knows it exists.
- Address
- Place Jules Janssen, 92190 Meudon
- Phone
- +33 1 41 14 80 00
- Opening hours
- 08:00–20:00 from 1 April to 30 September; 08:00–18:00 from 1 October to 31 March. Open all year except during exceptional closures.
- Admission
- Free and unrestricted access to the terrace and the national domain.
- Getting there
- Meudon Val Fleury (RER C) then bus 169, 289 or 389, stops “Observatoire” or “Terre Neuve”. Car park on site.
What you are standing on
The terrace is the surviving piece of one of the great lost palaces of France. Abel Servien had it built between 1649 and 1654: 260 metres long, 140 metres wide, 14 metres high. Louvois then commissioned André Le Nôtre to lay out the gardens, and the Grande Perspective he drew still runs across the domain and into the forest.
Louis XIV bought the estate in 1695 for his son the Grand Dauphin, who built the Château Neuf in 1706. The Château Vieux burned in 1795 and was demolished in 1803. The Château Neuf burned for three days in January 1871, during the Franco-Prussian war.
In 1874 the State installed an astrophysical observatory in the ruins. Jules Janssen, who had discovered helium in the solar spectrum, took charge and moved in during 1876. The great dome you see today sits on the foundations of the Château Neuf.
Visiting the observatory itself
This is where visitors are often disappointed, so let us be clear: the terrace is freely open, but the observatory is a working research centre, not a museum. It has no regular public opening hours.
It does open for the European Heritage Days each September, with guided tours led by the scientists, including the Grande Coupole and its great refractor. Booking is compulsory and places go quickly.
What to do while you are here
Walk the length of the terrace at the end of the afternoon, when the light comes back off the city. The Orangery, built in 1657 and still housing its orange trees, is at the far end. The forest starts just behind you, on the axis of Le Nôtre's perspective — which makes this the natural starting point for a walk down to the ponds.