Astrolabe Catalogue

 

Date 1613
Place Europe
Material Brass
Inventory no. 47367
Acquisition Presented by Lewis Evans in 1924

Back


There is a volvelle on the back of this instrument. It bears at least two scales, numbered 2 to 22; 0 to 12; o to 21; and 0 to 11. The volvelle is shaped like a disc with the head and tail of a dragon, suggesting that this might be a set of scales used to calculate lunar nodes or eclipses.

The back contains 4 scales of the following types:
Type
(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 10th day and end of the month days Circular, concentric Circular scale second in from the outer scale - refers to the full circle.
Other 1 - 90, None Every 1  Circular, concentric Circular scale third in from the outer scale - refers to the full circle.
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