Welcome to Sonnenborgh

Free exhibition Sunday 31 August - Come & see the stolen meteorite

In the night of 18 to 19 August a safe was stolen from the observatory. In the safe was one of the five meteorites who where seen falling and found in the Netherlands. This meteorite is often called Serooskerke meteorite, but a common synonym is Ellemeet meteorite. The meteorite fell from space on August 28 1925. It broke up in the sky and at least two fragments were found near the villages of Serooskerke and Ellemeet. In the safe were some other meteorites as well.

Fortunately the thiefs were not after the meteorites. They were all found near some tennis courts by players looking for their tennis balls in the bushes next to the court.

To celebrate the return of the meteorites Sonnenborgh museum & observatory will be open for free on Sunday 31 August. The returned meteorites wil be in the exhibition. Experts are available for questions. And if you found a strange stone during your hollidays and think it might be a meteorite, our experts can evaluate the stone for you.


Discover the secrets of Sonnenborgh. Go behind the thick walls of the 16th Century Bastion to search for cannon emplacements. Climb the stairs up to the 19th Century telescope domes and gaze at the stars. Imagine yourself as a meteorologist and carry out exciting weather experiments or take a close up view of the Sun with the aid of a special solar telescope. The observatory and meteorological institute were established in 1854 on top of the old Sonnenborgh bastion which dates back to 1552. Scientists conducted research into the weather, the stars and planets, as well as time measurement. Today Sonnenborgh is both a museum and an observatory, and there is still a great deal to see and do.

The Sonnenborgh Bastion
Experience the special history of a Utrecht bastion. Return to the 16th Century and seek out the canon emplacements in the casemates behind three metre thick walls. Take a peek into the old well, utilised as a latrine in the 16th Century. From 1998 to 2003 these fortifications were intensively studied and restored. Following the construction of the Zocher gardens in around 1840, a large portion of the bastion was buried underground. The entry gate was the first structure to be brought to light. The archaeologists then made further significant finds, such as a chemistry laboratory dating back to around 1700AD. Of all the bastions in Utrecht, Sonnenborgh has remained the best preserved. Even in comparison with other North European examples, it is in exceptionally good condition. Take a stroll past the unique spots of this 16th Century bastion and become acquainted with its long hidden secrets.

The Observatory (Sterrenwacht)
Sonnenborgh is the oldest cupola observatory in the Netherlands. There are four large telescopes with which to study the universe. Until 2002, the Merz Telescope from 1863 was the most important (night) telescope in the observatory. This instrument was one of the largest of its kind in the world. Today the computer-controlled Gala Telescope is the primary night telescope here. Activities include star viewing evenings, courses and special lectures. Come and take a look at the Moon and planets for yourself and pick out almost invisible gas nebulas.
Star Viewing Nights at Sonnenborgh

The Utrecht Meridian
For centuries many cities had their own observatory in order to ascertain the time. The stylish Meridian Room at the Sonnenborgh was also constructed for this purpose. Up until the start of the 20th Century, the stars were mapped to measure the passing of time, with the aid of a special telescope positioned on the Utrecht meridian. Come and check what the actual time is at longitude 5° 07' 46.67"!

Weather and Sun
The weather: everyone experiences it but anyone who wishes to find out more can do so at the Sonnenborgh museum and observatory. Meteorological research began here in the 19th Century. In 1854 the famous meteorologist C. Buys Ballot erected the KNMI (Royal Netherlands Meteorological Institute) and the observatory on top of the fortifications. As a researcher, Buys Ballot was a practical man: he oversaw the taking of measurements, introduced the weather forecast and aided shipping traffic with the provision of storm warnings, made visible with the use of a semaphore. He also brought about the cooperation of international meteorologists. How the weather was observed can be seen firsthand by the visitor through the historic instruments displayed in the collections of the KNMI and the University Museum. Can you remain standing during a force nine gale? And how is that related to Buys Ballot's Law? Test it out yourself and discover what comes into view through study of the weather.

At the Utrecht observatory one star has been examined very extensively, the Sun. Thanks to the Utrecht astronomers, we know what the Sun is made of and how hot it is. But how do you decipher the mysteries of a glowing hot ball of gas without going there? It is made possible with the special sun viewer or spectroheliograph. This instrument (the third example of its kind ever built in the world) consists of a 7 metre long telescope and behind it, a 12 metre long spectroscope. This splits up the light of the Sun into the colours of the rainbow. How this research works in practice and the ingenious inventions used for conducting it can be seen in the Weather and Sun Room. Wonder at the longest sun spectrum in the world and conduct experiments to discover which gases the Sun consists of.

Opening Hours and Prices

telescope positioned on the Utrecht meridian
weather and sun
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