Astrolabe Catalogue

The back contains 6 scales of the following types:

Type (click to view scale details)	Range & Units	Numbered	Geometry	Location
Degree	0 - 90, Degrees of arc	Every 5 degrees	Circular, concentric	The entire outer circle on the back of an astrolabe.
Zodiacal signs	0 - 30, Zodiacal divisions, equal or unequal	Every 5	Circular, concentric	Circular scale immediately inside the outer scale - refers to the full circle
Calendar	Days of year	days	Circular, eccentric	Circular scale second in from the outer scale - refers to the full circle.
Solar cycle	Days of year	days	Inner Circular, concentric	First circle within shadow square.
Shadow square	0 - 12, Fingers	Every 2 fingers	Box	Right hand bottom face of the shadow square (in LR)
Shadow square	0 - 12, Fingers	Every 2 fingers	Box	Right hand vertical face of the shadow square (in LR)

The back is inscribed:

Transcription	Translation	Notes	Type
صنعه ٳبراهيم بن سعيد السهلي بمدينة طليطلة في شوال سنة تص الهجري	The work of Ibrāhīm ibn Saʿīd as-Sahlī in the city of Toledo in Shawwāl in A.H. 460.		Maker's signature