We came as part of a larger group and received an interesting show with plenty of astronomy explanations. All instruments and the complete observatory are in great conditions - despite it was already built around 1901.
It looks like Zurich is loaded with nice high views, be it from church towers, a nearby mountain an here an observatory. It is difficult to find the entrance but with some help from locals things work. However, I think high views of Zurich tend to become repetitive after trying them from different locations.