The museum is dedicated to astronomy and holds the collection of the former institute of astronomy and astrophysics of Utrecht University. It is on site of the former observatory. The lantern slide collection consists of c. 3000 lantern slides that were mostly used in university teaching. Slides show sketches and photographs of astronomic phenomena, instruments, important astronomers and Utrecht observatory - the Sonnenborgh. Some slides are produced by commercial distributors, but most are of own making. Slides dates from circa 1895-1956. After the closing of the department of astrophysics at Utrecht University, the museum became independent. The slide collection is now under the curatorship of Utrecht University Museum.