Astrolabe Catalogue

The back contains 6 scales of the following types:

Type (click to view scale details)	Range & Units	Numbered	Geometry	Location
Altitude	0 - 90, Degrees of arc	Every 5 degrees	Circular, concentric	outermost scale on the front of the limb
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, concentric	None
Unequal hours	1 - 6, 1/12 of daylight	Every 1 hours	Arc	Upper left quadrant (inside circular scales)
Unequal hours	1 - 6, 1/12 of daylight	Every 1 hours	Arc	Upper right quadrant (inside circular scales)
Shadow square	1 - 12, Fingers	Every 2 fingers	Box	Left hand vertical 'face' of the shadow square (in LL)
Shadow square	1 - 12, Fingers	Every 2 fingers	Box	Right hand vertical face of the shadow square (in LR)
Shadow square	1 - 12, Fingers	Every 2 fingers	Box	Left hand bottom face of the shadow square (in LL)
Shadow square	1 - 12, Fingers	Every 2 fingers	Box	Right hand bottom face of the shadow square (in LR)

The back is inscribed:

Transcription	Translation	Notes	Type
الحمد لله هذا الأسطرلاب حبس على المسجد الأعظم من ثغر طنجة علاه الله بمنه آمين	Praise be to God. This astrolabe was given as a bequest to the Grand Mosque of the port of Tangiers, may God elevate it with His grace. Amen.		Miscellaneous