The astrolabe was used just as much for court and popular astrology as it was for making purely astronomical calculations. Making predictions about the future and casting horoscopes were activities embedded in the social fabric of both European and Islamic societies. The astrolabe provided a convenient way of collecting the basic information required to accomplish such tasks. In fact, the word “horoscope” is derived from the Greek words hora (time) and skopos (observer). The astrolabe “observed time” through the calculation of positions and relationships of celestial objects like the stars, sun, moon, and planets. The users interpreted these results and made predictions about a person’s personality, the length of their life, the progress of their illnesses, and the failure or success of their undertakings. The astrolabes in this exhibition illustrate these complimentary and often overlapping roles assumed by astronomy and astrology as well as their practitioners.

Equatorium and Astrolabe
Late 15th century
Maker Unknown
Southern France or Northern Italy
Billmeir Collection
This equatorium was likely designed for medical astrology, indicated by the additional rete and an astrolabe plate with lines for fever prediction. The three circles on the front use Ptolemy’s rules for planetary motion to calculate the positions of the moon, Mercury & Venus, and Mars, Jupiter, & Saturn. The sun is included with the stars on the astrolabe’s back, despite Ptolemy’s belief that the Sun was a planet.

Astrolabe and Astrological Volvelle in brass
Late15th century
Maker Unknown
Lewis Evans Collection
This astrolabe has an unusual rete design and eight concentric astrological volvelles on the back. The back itself is engraved with the names and numbers of the astrological houses. The volvelles feature a calendar and zodiac, the ruling planets for each sign, corresponding elements, and the lunar phases.

Astrolabe, Syro-Egyptian
1227/8 (dated 625 A.H.)
Made by Abd al-Karim al-Misri
Location Unknown
Brass with Gold and Silver damascene work
Lewis Evans Collection
The back of this astrolabe is engraved with zodiac pictures, the 28 mansions of the moon and an astrological table. The gold inscription on its rim is dedicated to an early 13th century ruler of Mesopotamia. One of its plates may feature the earliest surviving tablet of ecliptical coordinates.


The astrolabe’s instructional value and its popularity were notably increased by the invention of Gutenberg’s printing press in the mid-15th century. As a result of this invention, the instrument could be easily reproduced and diffused more widely in instructional publications. This made the astrolabe accessible to a much broader public. Students, tradesmen and professionals could join royalty in experimenting with its use and construction. The printing press facilitated the trade, travel and consumption of astrolabes through these different social groups and encouraged the use of the instrument even further into Europe.

Paper Astrolabe,
Made by Georg Hartmann
Pasteboard, Paper, Wood, and Brass
Lewis Evans Collection
Early paper instruments are rare, but there are a number extant from Georg Hartmann. He appears to have printed the paper astrolabes from the same plate and simply changed the year. This example is signed on the blank rim by Leonardo Botalli of Asti, a medical author and physician to Charles IX and Henri III of France.


Many finely crafted astrolabes were built for wealthy patrons who could afford to support their design, production and innovation. They have been preserved as aesthetically impressive objects, often illustrating the status of their patron more than the precision of their instrumentation. Many existing astrolabes are dedicated to Islamic and European nobility and feature inscribed dedications and crests. These are often elaborately decorated and incorporated into the astrolabes’ structural elements. Such impressive features often gained or encouraged the continued patronage of an instrument-maker and helped to maintain the continued importance of the astrolabe more broadly

1647/8 (dated 1057 A.H.)
Made by Muhammad Muqim al-Yazdi
Lewis Evans Collection
This 18.25 lb. astrolabe was dedicated to the Safavid ruler Shah Abbâs II, whose name is in the ecliptic circle decoration. An inscription on the topmost decoration is addressed to “The supreme prince, the sul_ân, the most just, the most great, lord of the centres of command, remover of the causes of tyranny and rebellion, king of the kings of the age….”.

Made by Thomas Gemini
Transferred from the University Observatory
Thomas Gemini made this astrolabe for Queen Elizabeth I. Its rete features the Flemish tulip, and there is a Gemma Frisius style universal projection on the back. The astrolabe was later obtained by Nicholas Greaves, the brother of an Oxford astronomy professor, for a scientific journey in Levant in 1637-40.