"Palaeo" Astronomy
That is, if you consider 1540 "ancient"...
This article from today's paper made me aware of this library. While exploring the site, I found their Digital Collections, where you can view - online - seminal star atlases from the collection, including Johann Bayer's 1603 Uranometria and John Flamsteed's 1776 Atlas Céleste.
It's open to the public, and free... Never thought I'd have a chance to see De Revolutionibus, Sidereus nuncius or Principia mathematica, let alone all three in the same place. It seems a trip is in order.