Astrolabe Catalogue


Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 1221/2 (A.H. 618)
Maker Muḥammad ibn Abī Bakr
Place Iṣfahān
Material Brass
Inventory no. 48213
Acquisition Presented by Lewis Evans in 1924


The back of instrument contains a set of calendrical diagrams. The upper window represents the phase of the moon. The rectangular window provides the age of the moon. Finally, the lower moving diagram indicates the relative positions of the sun and moon and the sun's location in the zodiac. Attached to the inside of the back plate are five gears, which rotate as the rete rotates and cause the diagrams on the back of the instrument to reflect the current celestial phenomena..

The back contains 1 scales of the following types:
(click to view scale details)
Range & Units Numbered Geometry Location
Zodiacal signs 0 - 30, Zodiacal divisions, equal or unequal Every 10  Inner circular, eccentric None
The back is inscribed:
Transcription Translation Notes Type
فلك يريد به هلالاً طلعاً متزيداً ويعود في نقصان ويريد جرما النيرون كليهما يتقابلان به ويجتمعان ويريد مبلغ سير كل منهما في العام أو في الشهر أو في اﻵن نتجته همة عالم بصنائع بنيت على التحقيق والبرهان انظر ٳلى فلك يريد عجابياً فيه تبين حكمة الرحمن حركاته شتى بفرد محرك وله معاني فوق كل معاني في سنة خيع (؟) هجرية ‘Star’ [or 'Heavenly Body'] means an ascending and increasing crescent which decreases again. ‘Sun’ and ‘Moon’ means that both of them face each other and meet. The duration [extent?] of the way of each of them in the year, or in the month or a particular time is a result of the design of him who knows the sciences which are based on methods of verification and demonstrative proof. ‘Look at the heavenly bodies’ means something wonderful in which the wisdom of the Merciful appears through different motions with a single mover. He has different meanings above all meanings. In the year 618 A.H. Around the entire rim General explanation
زيادة نور القمر ونقصانه Increase and decrease of the light of the moon Around the upper circular (lunar) window Scale label
عدد أيام الشهر Number of the days of the month Above and below the small rectangular (age of moon) window Scale label
جرما النيرين يجتمعان يوم الاجتماع ويتقابلا يوم الاستقبال Sun and moon meet on the day of conjunction and they face each other on the day of opposition. On the volvelle within the lower window Scale label
صنعة محمد بن أبي بكر بن محمد الراشدي اﻹبري اﻹصفهاني Made by Muḥammad ibn Abī Bakr ibn Muḥammad al-Rāshidī al-Ibarī al-Iṣfahānī. Main inscription across the centre of the back Maker's signature
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