Koninklijk Eise Eisinga Planetarium

Franeker is a small town in Friesland with a university past, and it is home to one of the most remarkable scientific instruments in the world. The Eise Eisinga Planetarium is a working model of the solar system, built in the late eighteenth century by a self-taught astronomer who made his living combing wool. It is still driven by its original mechanism and is regarded as the oldest functioning planetarium in the world, and in 2023 it was added to the UNESCO World Heritage list.

The story behind it is worth telling. In the 1770s, a local pastor published a prediction that a conjunction of planets in 1774 would cause the end of the world, and the rumour frightened many people in the province. Eisinga, who was fascinated by astronomy and mathematics, was determined to show that there was no danger. He began to build a model of the solar system in the ceiling of his own living room, which took several years of work and was completed in the early 1780s. His family and friends helped, and the result is a very accurate and beautiful piece of craftsmanship.

The mechanism is the point. The ceiling of the room carries the planets, the sun and the moon as painted discs and small balls, arranged on a scale of one millimetre to a million kilometres, and a wooden clockwork driven by a pendulum clock moves them at the speed of the real orbits. Visitors can stand in the room and look up at the heavens, watching the planets as known to the astronomers of the time, from Mercury to Saturn. The calendar, the phases of the moon and the dates of eclipses can also be read from the instrument. Over two centuries have passed, and it still keeps time, which is a testimony to Eisinga's skill.

The house is now a museum. The family's living space has been preserved, with a box bed, and other rooms display astronomical instruments, Eisinga's workshop and exhibits on space and the solar system. A king of the Netherlands bought the planetarium in the early nineteenth century to save it, which explains the word Royal in its title. A short film explains the story, and the museum has activities for children.

Franeker offers other sights, including the town hall, the Martinikerk and old streets. The museum suits families, science enthusiasts and anyone who admires patient craftsmanship. A visit takes about an hour. Check the opening times and ticket details before going, and be prepared for steep stairs.