Visited during school holidays, and not too crowded! All the staff we encountered were friendly, enthusiastic and added to the experience. Small, but beautiful site - historic building, lovely grounds and fantastic views. Did the guided tour, 3D show and viewed the sun through the telescope... Day visits are drop in, but need to book for any of the evening tours. Entry is free, but you do pay extra for the 3D shows etc. (unless you are a member with the Powerhouse Museum, then during the day - these "extras" are included). At the moment, also a photographic exhibition on, (& Lego room for kids) so something for everyone.