The Ivory quadrant signed by Abu Tahir, an iranian warlord and ruler of Qarmatian state in Bahrain is conserved at the Benaki Museum of Islamic Art. Dating from 741 in Syria it is described as a rare specimen, serving two geographic latitudes; Cairo and Damascus. The quadrant is an earlier variation of the astrolabe, an elaborate inclinometer operating through astronomical calculations. At the time, celestial knowledge was necessary to position Man within the universe and ground truths about the world surrounding him. Replaced by watches, clocks and phones nowadays, the importance of astrology doesn’t seem as relevant in measuring time. This object is particularly interesting to discuss as it reminds us of the resourcefulness of our ancestors and the lost connection we now have with the sky. This two dimensional map is a vital insight into Greek and Muslim cultures and art correlating religion, science and astrology.
Invented by the Greeks in the 2nd century BC, knowledge of the astrolabe was transmitted to Muslims through translations of Hellenistic and Byzantine texts into Arabic language. This scientific translation was done in Baghdad in the Abbasid era with earliest traces dating to the 9th century. Much like the astrolabe this time telling device replicates the model of the universe in your hand’s disposition but it doesn’t serve a unique purpose for time measuring, it could also be used in measuring angular heights of a star, building or mountain. Moreover it could determine the direction of Mecca which is faced during prayer.
The quadrant is a measuring device with a graduated arc of 90°, it’s one-fourth of a full circle. As it’s smaller and lighter than the original astrolabe, it was easily transportable therefore it could have been used by not only astronomers determining an eclipse but also by merchant travellers to navigate through the night sky. Celestial navigation allowed sailors to learn that the Pole Star could be used as a navigational landmark which opened new possibilities for exploration and trade routes.
The concept of stereographic projection originated in 330 BC, coming in various shapes, sizes and forms for portability or display. Evolving throughout history, earlier astrolabes were particularly simple and primitive as this very quadrant. However, the most recognisable and common trait to all is the magnificent art accompanying astrolabes representing precision and craftsmanship. Even on this quadrant there are meticulously drawn arabic inscriptions and perfectly drawn symmetrical patterns reflecting the asymmetrical sky. With time the patterns and assemblage became more complex reflecting unique artisanal skills and power of knowledge. Mediating between the divine heavenly imagery of astrology and mathematics, the quadrant represents a system of thought marking a turning point in navigation which ensured a culturally emblematic position of the astrolabe in society.