Using an Horary Quadrant

Finding the time of day with an horary quadrant by measuring the Sun’s altitude, from Gregor Reisch, Margarita Philosophica, 1504.

Caption:
Using an horary quadrant to find time of day by measuring the Sun's altitude.
Type: Illustration
Credit: Smithsonian Institution Libraries
Origin: Smithsonian Institution
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Using an horary quadrant to find time of day by measuring the Sun's altitude.