Treasures of the North 3
A tiny solar system on the ceiling
Door Christien Boomsma
By Christien Boomsma
Christien Boomsma
Achtergrondcoördinator en wetenschapsredacteur Volledig bio » Background coordinator and science editor Full bio »It’s a lovely story. Great, even.
The year is 1774, and a Frisian preacher published a piece predicting the end of times. In May of that year, Mercury, Venus, Mars, Jupiter, and the moon will be in conjunction, and they will fling the earth from its orbit.
The Leeuwarder Courant writes an article about it, causing a panic. Even after the preacher’s writings are banned, people remain apprehensive.
That’s when Eise Eisinga, wool comber and astronomer, realises he can help. He builds a planetarium on the ceiling of his living room in Franeker so people can see for themselves that they don’t need to worry about planets crashing into each other.
World heritage
It is a story that still circulates. It’s too bad, then, that it isn’t true.
The Eise Eisinga Planetarium
For seven years, astronomer and wool comber Eise Eisinga worked on building a planetarium in his living room in Franeker. He finished the project in 1781.
The planetarium shows the position of the Earth, Moon, and the five planets that were known at the time: Mercury, Venus, Mars, Jupiter and Saturn. At the centre of the planetarium is the Sun. Just when the project was finished, the planet Uranus was discovered. But there wasn’t any room to include this new planet.
The mechanism consists of a pendulum clock and a complex set of cogs, that is still in perfect working order, 250 years after it was built. Every four years, a leap day has to be manually added.
The planetarium is open to visitors from Tuesday to Sunday; the entrance fee is 6 euros. Franeker is an hour away by car and seventy-five minutes by train.
‘I always say, if you want to explain it, all you need is five minutes and a piece of paper’, says science historian Arjen Dijkstra. ‘There are also some great drawings from that time that show exactly what the stars looked like back then.’ He doesn’t think that Eisinga was telling the scared citizens that they’d simply have to wait a few years for him to finish his project.
It took Eisinga, his father, and his brother seven years before the planets, connected to a large pendulum clock in the attic, started moving across the ceiling in 1781. Nearly 250 years later, the planets still make their way across the ceiling.
This makes the Eise Eisinga Planetarium, which was recently awarded the status of World Heritage site, the oldest working planetarium in the world – less than a hundred kilometres from Groningen. ‘I must have visited it ten thousand times by now’, says Dijkstra, who wrote a biography on Eisinga. ‘And I’m still blown away by its ingenuity.’
The miniature earth takes 365 days to make its way around the miniature sun. The scale model of the planet Saturn even takes twenty-nine years before completing its circle of Eisinga’s living room. ‘On top of that, the design is just really gorgeous. You don’t have to be interested in the stars or maths to appreciate it.’
But why did Eisinga build his planetarium?
European ideal
In part, says Dijkstra, simply because he had the skills. Eisinga was a maker, a tinkerer, just like his dad. ‘He would just build a boat and take Eise out on the water.’ Eise was also brought up with a love for maths and astronomy. As a teenager, he would read the mathematical works by Euclid.
He also had time. While Eisinga is often considered a simple workman, he was in fact the CEO of a successful wool company. ‘He bought the wool’, says Dijkstra, ‘but there were literally hundreds of people, mainly women, who processed it for him.’
Knowledge had to be shared; it was about educating the masses
But the biggest reason for Eisinga to build his planetarium was because it matched the European ideals of the time. ‘In those days, it wasn’t just about amassing and increasing knowledge’, adds historian Nikolaj Bijleveld. ‘The knowledge had to be applicable and shared with other people. It was all about educating the masses.’
Dijkstra and Bijleveld are currently finishing up a book in which they place Eisinga in this greater European tradition. While the planetarium is unbelievably beautiful and well-made and unique, it never would have reached the status of World Heritage site if it wasn’t part of something bigger.
‘It was a time when a new middle class gained access to knowledge through education, national and international journals, and association meetings’, Bijleveld explains. ‘The didn’t just share their own knowledge, but also their own research. The idea was that people would benefit from this knowledge. Not in terms of social mobility, but of prosperity.’
Devotees
What’s interesting about this period in history is that people were doing this in addition to their day job. Eisinga ran his wool company and studied astronomy. Groningen preacher Jacob Uilkens was on the pulpit every Sunday but used his rectory’s garden to improve seeds and develop new agricultural techniques.
You can immediately see whether there’s a solar eclipse somewhere
At the same time, German farmer Georg Palitzch was also studying astronomy. He was the first person to spot the comet that Halley had predicted would return, in 1758. His observations were published internationally and nobility came to his house to meet him. And illegitimate French officer Alexandre Moreau de Jannes, stationed in the colonies, used this to study zoology, geography, and geology.
It resulted in a movement of people that Dijkstra and Bijleveld call ‘devotees’. They feel terms like ‘hobbyist’ or ‘amateur scientist’ don’t do them justice. ‘These terms have a negative connotation that they don’t deserve’, says Dijkstra.
‘Don’t forget, professional scientists like we have today only came to be halfway through the nineteenth century’, adds Bijleveld. ‘They didn’t have academics like we have today, but they did have this ideal of amassing and sharing knowledge. These devotees made use of all the opportunities this gave them.’
Enthusiasm
Even the professors at universities were mainly educators rather than scientists. They taught classes, both publicly and privately, and used their free time to do research or write books. ‘Not because it was their job, but because they were devoted’, says Dijkstra.
Eisinga and his planetarium are a great example of the enthusiasm that was so common at the time. Using nothing but his imagination, his brain power, and a piece of slate to make calculations on, he was able to build a miniature solar system. ‘There’s so much information there’, says Dijkstra. ‘When you walk in, you can immediately see whether there’s a solar eclipse somewhere.’
Visitors who went to the planetarium also noticed this. There’s a good reason that Willem I bought the planetarium so it would belong to the Dutch state in 1825. ‘No one has ever managed to make something as amazing as this since’, says Dijkstra. ‘They tried to compete with Eisinga in Zeeland in 1791. Middelburg invested a lot of money, but their planetarium is less accurate and doesn’t have as much data. It’s pretty cute, and you can still visit it. But it keeps jamming.’
Nikolaj Bijleveld, Arjen Dijkstra, Samuel Gessner (ed.), Devotees of Science. Cultivating Astronomy, Technical and Natural Knowledge around 1800, Amsterdam University Press (2024)