Sonnenborgh
Sonnenborgh is the name of the southeastern bastion of the historic fortification of the city of Utrecht in the Netherlands . It houses the astronomical observatory of the University of Utrecht , which is now also used as a museum and, together with the University Museum , attracts 60,000 visitors annually.
history
The Sonnenborgh Bastion was built in 1552 by order of Emperor Charles V as part of the city fortifications of Utrecht. Later it also housed scientific institutions. The University of Utrecht has been using the bastion as a herb garden since 1639. In 1695, the city council of Utrecht financed the chemist Johann Conrad Barchusen a laboratory here. In the 1840s, the Dutch scholar Christoph Buys Ballot set up a cellar for magnetic observations on Sonnenborgh. Frederick Wilhelm Krecke (1812–1882) began here on December 1, 1849 with regular weather observations. In 1853 Buys Ballot founded the observatory. From 1854 to 1897, Sonnenborgh was also the seat of the Royal Netherlands Meteorological Institute . From 1937 to 1963 Marcel Minnaert was director of the observatory and had his living quarters there. The current director is his pupil Cornelis de Jager .
When Jan David Zocher laid out the Zocherplantsoen park from 1850 , large parts of the bastion were covered with earth. From 1998 to 2003 these areas were excavated, archaeologically examined and restored. Today parts of the bastion are used as a museum. Until 2013 the Sonnenborgh was also the seat of the De Koepel Foundation , a Dutch umbrella organization for the popularization of astronomy , meteorology and space travel .
Museum and observatory
Museum and observatory Sonnenborgh ( Dutch Sonnenborgh - museum & sterrenwacht ) represents a unique combination of military and science museum. On a tour you can visit the casemates of the historical fortifications with their 3 meter thick walls. A number of astronomical and meteorological devices are presented to the visitor in the area of the observatory. The sunlight is directed directly into the sun room accessible to visitors via a coelostat . With this device, the Utrecht Solar Atlas (a photometric atlas of the solar spectrum ) was created in 1940 , which is still used today in many observatories. In the north tower one is also to observe the Sun, Fraunhofer - telescope from 1826, combined with an H-α-filter of Bernard Lyot . An achromatic 200 mm Lichtenknecker VAF 200 refractor and a Celestron-14 reflector telescope for night-time observation of planets and nebulae are housed in the domed east tower . The 260 mm telescope from Steinheil dates back to 1863 and was fitted with a Merz lens in 1888 in the south tower of the observatory. The Meridian Hall is located between the north and south towers , named after the meridian circle set up here . The museum also has a library, a lecture room and the cycloid room , named after the arched shape of an outer wall in the form of a cycloid , which is used for changing exhibitions.
The observatory has the IAU code 015 .
Individual evidence
- ↑ Homepage ( page no longer available , search in web archives ) of the University of Utrecht, as of December 29, 2008
- ^ Moritz Snellen: Buys Ballot . In: Meteorologische Zeitschrift 8, 1891, pp. 1-6
- ↑ former homepage ( Memento of 13 December 2013, Internet Archive ) Foundation De Koepel
Web links
Coordinates: 52 ° 5 ′ 7.5 ″ N , 5 ° 7 ′ 45.6 ″ E