Ooops! and Ooops again!
Those of you who’ve heard me speak about the New School with slides have probably heard me refer to this as an astrolabe:
Brett Miller just emailed me and asked (as part of a very nice email) “isn’t that an orrery, not an astrolabe?”
It appears that I’m going to have to update my commentary. Thanks, Brett!
[And thanks Scott–I misspelt orrery, now corrected.]