Catoptric sundial, Trinità dei Monti Convent
This catoptric sundial is the most spatial and temporal drawing that measures ‘the hour of the stars’ utilising small mirror that tracks the movement of the sun across the vaulted ceiling. For other type of dials see below post.
Ivana Wingham 
thank you for posting this tiny treasure. Rome is indeed “La Città Eterna”, not only enduring, but constantly revealing more delights.
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