Map of Eise Eisinga Planetarium
The coordinates shown for all tentative sites were produced as a community effort. They are not official and may change on inscription.
After having visited all Dutch Tentative Sites on European soil, I believe that this is the strongest proposal. Its subject, astronomy explained to the general public, is pretty unique. Also, it can fill a gap in the List as the history of science is currently deemed underrepresented. Especially the long regional and cultural tradition of the 'lay scholar' is praised here.
The Planetarium lies in the Frisian town of Franeker. This is a prominent city in the history of the Netherlands: it held the second oldest university. It has a marvellous city hall for example, and many other fine old buildings.
Eise Eisinga was an autodidact who built this small Planetarium or Orrery in 1781. It is the oldest of its kind that still works. He constructed his model of the galaxy on the ceiling of his living room. It is a sky-blue wooden structure, with moving elements steared by an intricate mechanical clockwork structure on the attic above. He received a lot of visitors in his time who came to see this, both prominents and schoolchildren.
His former house now is a little museum. The entrance fee is 4.5 EUR. A fifteen minute explanation of the structure is included. It's really fascinating to see how it all works: how the planets move relative to each other, but also what time it is, which date, which year. Eisinga also left behind an entire manual about how it all functions, including instructions for future caretakers.