Astrolabe Catalogue

The back contains 13 scales of the following types:

Type (click to view scale details)	Range & Units	Numbered	Geometry	Location
Altitude	0 - 90, Degrees	Every 5 degrees	Circular, concentric	Upper right quadrant of outer circular on back of instrument.
Altitude	0 - 90, Degrees	Every 5 degrees	Circular, concentric	Upper left quadrant of outer circular on back of instrument.
Declination	Summer solstice - Winter solstice, Zodiacal divisions, equal or unequal	Not numbered	Arc	Upper right quadrant (inside circular scales)
Altitude of noon sun	26 - 47, Degrees	Every 3 degrees	Arc	Upper right quadrant (inside circular scales)
Azimuth of Qibla	Cities	Not numbered	Arc	Upper right quadrant (inside circular scales)
Cotangent	0 - 35, Feet	Every 5 feet	Circular, concentric	Lower left quadrant of outer circular on back of instrument.
Cotangent	0 - 45, Fingers	Every 5 fingers	Circular, concentric	Lower right quadrant of outer circular on back of instrument.
Zodiacal signs	Aries - Pisces, Zodiacal sign	Not numbered	Inner Circular, concentric	half circle inside the outer circle (on mashriqi astrolabes) - covering LL and LR
Terms	0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal	At each term	Inner Circular, concentric	half circle inside the V circle (on mashriqi astrolabes) - covering LL and LR
Faces	0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal	Not numbered	Inner Circular, concentric	half circle inside the VI circle (on mashriqi astrolabes) - covering LL and LR
Shadow square	0 - 7, Feet	Every 1 feet	Box	Left hand vertical 'face' of the shadow square (in LL)
Shadow square	0 - 7, Feet	Every 1 feet	Box	Left hand bottom face of the shadow square (in LL)
Shadow square	0 - 12, Fingers	Every 1 fingers	Box	Right hand bottom face of the shadow square (in LR)
Shadow square	0 - 12, Fingers	Every 1 fingers	Box	Right hand vertical face of the shadow square (in LR)

The back is inscribed:

Transcription	Translation	Notes	Type
نقشه محمد مهدي اليزدي	Engraved by Muḥammad Mahdī al-Yazdī	Inscription in unusually-shaped cartouche. The inscription is worn and difficult to read	Maker's signature