Astronomer Biography
– Azophi
Abd al-Rahman al-Sufi, called Azophi in the west, was born in
the Persian city of Rayya, also known as Ray, in the year 903 CE. He died in the year 986 CE. He was a subject
in the court of Emire Adud ad-Daula in Isfahan, Persia. In Isfahan, Azophi
performed astronomical studies for Emire Adud. Much of his work was focused on
expanding the work of Greek astronomers such as Ptolemy. He identified a “cloud”
in the sky that turned out to be the Andromeda galaxy, M31. He also identified
a group of stars that would become known as the Large Magellanic Cloud. His
work sparked interest in astronomy throughout the Arab world at the time, and
has had a lasting impact on the astronomical community to this day.
Azophi’s most noted work is the Kitāb Stnrar al-kawākib
al-thābita, which translates to “Book on the Constellations of the Fixed Stars”,
which reviews and revises Ptolemy’s catalogue of the stars, the Amalgest, adding his own work to that of
Ptolemy. This book was so popular that it spread into the medieval Western
world and was translated into Spanish by Judah Moses ha-Kohen of Toledo in
1256. This is where the westernized version of his name, Azophi, came from. His
book organizes his thoughts on the constellations by discussing all the stars
contained in the constellation, adding his own thoughts and observations as to
the brightness, color, and position of each star as compared to those of
Ptolemy, correcting him in several cases; associating the Arabic names for the
stars with the western ones, a difficult task given that the Arab
constellations were completely different than those of the west; drawing the
constellations as seen in the sky and as seen on the celestial sphere; and
giving a table of all stars in the constellation, giving the magnitude and position
of each one, according to his own observations. The significance of his work
lay in the fact that his data was based on real observations of the sky. Many medieval
astronomers simply added constant values to those obtained by Ptolemy, to
account for the progression of the Earth, but Azophi actually observed and made
adjustments to Ptolemy’s figures.
He also wrote several other manuscripts, including a long,
involved manual on how to use an astrolabe, including many different uses
developed by himself. He also created an instructional book for a celestial
globe, describing in detail all of the starts and constellations shown on its
surface. He is even believed to have produced astronomical instruments of his
own, such as a silver celestial globe that was supposedly of his design reported
to have been found in Egypt around 1043, nearly a hundred years after his
death. His lasting work in the field of astronomical instruments has been a
major contribution to the widespread study and interest in astronomy for many
centuries.
Azophi’s works have had a lasting impact on the astronomical
community, his book on the positions of the stars is still used today to study
the long-term movements of the stars. There is a crater on the moon named after
him, surrounded by a ring of mountains twenty-six miles wide. He also inspired
many other astronomers throughout the centuries, and his research has
contributed to that of many other prominent astronomers throughout history.
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