Astrolabe Catalogue


Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date ca. 1370
Place England (?)
Material Brass
Inventory no. 47869
Acquisition Presented by the Misses M. E. and L. C. Hyett and by The Friends of the Old Ashmolean in 1955


The back contains 5 scales of the following types:
(click to view scale details)
Range & Units Numbered Geometry Location
Degree 0 - 90, Degrees Every 10 degrees Circular, concentric The entire outer circle on the back of an astrolabe.
Zodiacal signs 0 - 30, Zodiacal divisions, equal or unequal Every 10  Circular, concentric Circular scale immediately inside the outer scale - refers to the full circle
Calendar First day of month - Last day of month, Days of year Every 10 days Circular, concentric Circular scale second in from the outer scale - refers to the full circle.
Saints' Days Days of year At each day days Circular, concentric Circular scale third in from the outer scale - refers to the full circle.
Shadow square 1 - 12, Feet Every 3 feet Box The lower two quadrants of the back of the instrument
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