Muslim Scientist

1. Ibn al-Shatir (1304 – 1375)
He was a muslim astronomer from Damascus who worked as timekeeper in the
Umayyad Mosque, and constructed a magnificent sundial for its minaret in 1371/72.

2. Ibn al-Shatir
Ibn al-Shatir invented
the first Astrolabic clock in the early 14th century.
His most important astronomical treatise was the
Kitab nihayat al-sul fi tashih al-usul
(The Final Quest Concerning the Rectification of Principles), in which he drastically
reformed the Ptolemaic models of the Sun, Moon, and planets, by his introducing his
own non-Ptolemaic models which eliminates the epicycle in the solar model,
which eliminate the eccentrics and equant by introducing extra epicycles in the
planetary models via the Tusi-couple, and which eliminates all eccentrics, epicycles
and equant in the lunar model.
Ibn al-Shatir's geometrical model was the first that was actually superior to the
Ptolemaic model in terms of its better agreement with empirical observations.
E. S. Kennedy discovered that Ibn al-Shatir's models were mathematically
equivalent to those Copernicus elaborated some 150 years later.

3. "Whereas Ibn al-Shatir’s concept of planetary motion was conceived in order to play
an important role in an earth-centred planetary model, Copernicus used the same
concept of motion to present his sun-centred planetary model.
Ibn al-Shatir played the most significant role in the development of theoretical
planetary models to account for the motions of the sun, moon, and planets and
overcome the problems associated with Ptolemaic planetary models.
His lunar model was also no different from the lunar model used by
Copernicus. This suggests that Ibn al-Shatir's model may have influenced
Copernicus while constructing the heliocentric model.
Though it remains uncertain how this may have happened, it is known
that Byzantine Greek manuscripts containing the Tusi-couple which Ibn al-Shatir
employed had reached Italy in the 15th century.
It is also known that Copernicus'diagrams for his heliocentric model, including
the markings of points, was nearly identical to the diagrams and markings used by
Ibn al-Shatir for his geocentric model, making it very likely that Copernicus may
have been aware of Ibn al-Shatir's work.

4. Another achievement of Ibn al-Shatir was the rejection of the Ptolemaic model on
empirical rather than philosophical grounds.
Ibn al Shā ir also compiled a set of tables displaying the values of certain spherical‐ ṭ
astronomical functions relating to the times of prayer.
The latitude used for these tables was 34°, corresponding to an unspecified locality
just north of Damascus.
These tables display such functions as the duration of morning and evening twilight
and the time of the afternoon prayer, as well as standard spherical astronomical
functions.