A look inside the incredible Paris observatory

Have you ever been inside the Paris observatory? Seeming it’s closed to the public, the answer is (unfortunately) most likely to be no. But we managed to get inside for this week’s podcast episode about the Paris Meridian Line, which runs right through the observatory. You can hear the episode below or anywhere you get podcasts.

Featuring prominently in the episode is Nicolas Lesté-Lasserre, a science historian and the community manager of the Observatoire de Paris. He showed me around this incredible 17th century institution, and he pops up in some of the photos below.

A very brief history of the observatory

This observatory is one of the largest astronomical centres in the world. It was founded in 1667, making it a few years older than the Royal Greenwich Observatory in the UK. Scientists in Paris were the first to discover four of Saturn’s moons from this very observatory. Nowadays, most of the researchers work at the observatory’s satellite campus in Meudon, though the Paris observatory still holds events for astrologists and students and there is a private museum downstairs.

Inside the coupole

I was especially interested to see inside the domed coupole on top, where a huge telescope can point out to the stars. The coupole is named after Francois Arago, the man who was instrumental in developing the Paris meridian line, which featured in this week’s podcast and which you can explore in pictures here. Just don’t call it the “Rose Line”… that’s just a fictional name for it from The Da Vinci Code.

Rooms to the side of the telescope dome include 150-year-old graffiti.

On the rooftops

To reach the dome, you need to ascend a marvellous staircase inside the main observatory building. From there, you walk across a mostly flat rooftop with views in all directions. In fact, it’s really easy to get a sense of the Meridian Line from up there given a tree-lined avenue runs north from the observatory, and a beautifully curated garden runs to the south with a prominent line through the middle.

Inside the observatory building

Inside the observatory’s main building, the ground floor contains a museum and a big meeting room, pictured below, while the second level features a huge strip on the floor from the north to the south side of the room, marking the exact location of the meridian line. The line is covered by plexiglass and includes astronomical engravings and measurements.

In the gardens of the observatory

The gardens are grand and feel like something from Provence rather than fairly central Paris. Arago medallions are dotted along the grounds – just out of reach for the public treasure hunt, but marking the way from north to south as they do across all of Paris.

That’s it for now! Be sure to listen to the podcast episode about this observatory and the Arago markers as it will give you a much deeper insight into the story. Thanks to Augusta Sagnelli for the pictures and to the observatory for letting us in. A huge thank you to the Patreon members who will soon get an insider’s look at this meridian line, and who have already seen a live video for next week’s episode on the letter B.

Enjoy the episode below, the start of the ABC-son, with A standing for Arago. I wonder what B will be!