Sonnenborgh - museum & observatory in Utrecht is an astronomical observatory and museum. It is located in Utrecht, The Netherlands. The university observatory (of the University of Utrecht) was founded in 1853 and from 1854 until 1897 it was the first home of the Royal Dutch Meteorologocal Institute (KNMI).

 Sonnenborgh (front)

It's housed in a former bastion built in 1552 by  Willem van Noort, also the best preserved part of the former city walls. Even in comparison with other North European examples, the bastion is in exceptionally good condition. The walls were demolished between 1829 and 1858 and replaced by the Zocher park.  In the middle of  the 19th century Professor Buys Ballot made ​​the Observatory move from the Smeetoren (where already meteorological observations were made)  to Sonnenborgh. In 1854 he founded at this place the Royal Dutch Meteorological Institute where it stayed till 1897. Sonnenborgh is the oldest cupola observatory in the Netherlands. There are four large telescopes to study the universe.

 South Tower with cupola 

For centuries many cities had their own observatory in order to ascertain the time, of course they named it here the Utrecht Meridian. The stylish Meridian Room at the Sonnenborgh was build for this sole purpose. 

Meridian Room 

One star has been examined here very extensively, the sun. By using the special sun viewer or spectroheliograph the scientists could see what elements the sun is made of and its temperature. 

Opening Hours: Tuesday to Friday 11am - 5pm and Sunday 1 – 5pm