Genuinely great attraction, go when it's quiet to ...

Genuinely great attraction, go when it's quiet to get your money's worth with minimum stress (would be very stressful when busy or with lots of kids). Take some video, they're happy for you to film/photograph everything and there's some pretty cool stuff. From illusions to optical effects and the world's first camera obscura (which gives the building its name) is in the roof; primitive yet impressive technology and a great little show on several times a day.