Three astrolabes.
https://assets.chaos.social/media_attachments/files/112/509/110/411/704/550/original/dbc9c798d6de0567.jpg
I also visited University of Oxford's Museum of Science, which showcases a lot of scientific instruments, including some super pretty and old astrolabes!
The museum didn't do a good of explaining how to use them, though. Need to look into that later tonight, maybe! :)
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