Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 1728/9 (A.H. 1141)
Maker Muḥammad ibn Aḥmad al-Baṭṭuṭī
Place North Africa
Material Brass
Inventory no. 52713
Acquisition Presented by Lewis Evans in 1924

Back



The back contains 8 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 Upper right quadrant of outer circular on back of instrument.
Altitude 0 - 90, Degrees of arc Every 5 degrees Circular, concentric Upper left quadrant of outer circular on back of instrument.
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 First day of month - Last day of month, Days of year Every 5 and end of the month days Circular, concentric Circular scale second in from the outer scale - refers to the full circle.
Lunar Mansions 16° Aries - 15° Aries, Lunar mansion Every 4 and end of the mansion  Circular, concentric Circular scale third in from the outer scale - refers to the full circle.
Unequal hours 1 - 6, 1/12 of daylight Every 1 hours Arc Upper right quadrant (inside circular scales)
Sine/Cosine 0 - 60, 1/60 of quadrant radius Every 5  Angle Upper left quadrant (inside circular scales)
Shadow square 0 - 12, Fingers Every 2 fingers Box Left hand vertical 'face' of the shadow square (in LL)
Shadow square 0 - 12, Fingers Every 2 fingers Box Right hand vertical face of the shadow square (in LR)
Shadow square 0 - 12, Fingers Every 2 fingers Box Left hand bottom face of the shadow square (in LL)
Shadow square 0 - 12, Fingers Every 2 fingers Box Right hand bottom face of the shadow square (in LR)
MHS Home | Contact Us | ©2006 Museum of the History of Science