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

Star viewing
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), and are Dutch spoken.
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 and Christmas (December 25th & 26th).