Sometimes people have special hobbies. The small town of Franeker used to be a sort of Frisian Oxford, hosting the second oldest university in the country (after the one in Leiden). Its cultural climate must have been quite stimulating, since it generated one of the most curious scientific achievements in 18th century Netherlands: a fully functional planetarium, built in a living room! The Eise Eisinga Planetarium is the oldest still functioning model of the solar system in the world. It was designed and built by a local amateur astronomer and mathematician, Eise Jelteszoon Eisinga, between 1774 and 1781. The mechanism shows in real time where the planets in our solar system are in relation to the sun. It also shows the date, the week, the year, the time of sunrise and sunset, the phases of the moon and the position of the zodiac. The mechanism is made of wooden hoops and discs and more than 10000 nails serve as gear teeth.
Eise Eisinga was born in 1744. He set up his own wool combing business in Franeker in 1768, but his biggest passions were mathematics and astronomy, and he went on studying them in his spare time. He had written a first book on mathematics by the age of fifteen, and two books on astronomy by the age of eighteen.
In 1774 Eelco Alta, a preacher from the nearby village of Bozum, made a prediction that terrified the people of Friesland: the apocalypse was going to take place on May 8th of that year. Mercury, Venus, Mars, Jupiter and the Moon were going to collide, pushing the Earth into the Sun. The planets were indeed going to form a rare alignment that year, and astronomers had predicted that, so many people believed him. Eise Eisinga decided to prove the prediction was wrong. He planned to build a working model of the solar system in his living room, to show that there was no danger of the planets colliding because they were actually far apart.
It sounds like a crazy idea, but Eisinga possessed the knowledge to make all the necessary calculations and the practical skills to build the model. Although he expected to finish it within six months, the planetarium eventually took him seven years to complete. Mrs. Eisinga must have been a very patient lady, since the model’s parts eventually spread all around their main room, which served both as living room and bedroom (not to mention the constant noise of the mechanism, which was installed in a sort of false ceiling). At one point Eisinga realized that the pendulum controlling the device was too long for the space he had designed for it. In order to make it work, he would have needed to cut a hole through the ceiling above the bed! That’s where his wife finally drew a line: she categorically opposed the change. Eisinga had to redo all his calculation to take into account a shorter pendulum, which would move faster. Due to this delay, and to the total amount of work involved, in the end the planetarium was finished only years later, long after the special planet alignment. The aesthetic part also took some time: besides the scientific interest, the device actually looks nice, it’s one of the most interesting house decoration ideas I have seen so far : )
The planetarium became famous immediately and attracted many visitors. King Willem I was one of them, and he was so impressed by the device that he decided to buy it in 1825. He agreed that Eisinga could carry on living in the house if he continued to provide guided tours for the public. Eisinga died on August 27th 1828, but his family took care of the planetarium until 1922. Currently, the Dutch government is preparing to submit a nomination for including it on UNESCO’s World Heritage List, a well-deserved recognition for such an original invention. The planetarium is open all year round, and guided tours in English and German are available. It is located in the center of Franeker, one of the eleven Frisian historical towns. It is well worth a Sunday trip.
See below the planetarium’s site: