Opening hours
Tuesdays to Fridays: 11 a.m. to 5 p.m.
Sundays: 1 to 5 p.m.

Stargazing nights
In fall and winter (October up until April) the observatory is open to the public every Friday and Saturday evening. The Star Viewing Nights are held between 8 and 9:30pm on Friday and 7:30 and 9pm on Saturday (special kids program). Every last friday of the month the stargazing nights are in English.
Every Sunday, year round, the observatory is open to the public to look at the Sun. Opening hours: 1 to 5 p.m.

Holidays
Sonnenborgh is closed on New Year’s Day (January 1st), the 2nd day of Easter, King’s Day (April 27th), Liberation Day (May 5th), Whit Monday, Christmas (December 25th & 26th) and december 31th.