TheConstantinople observatory of Taqi ad-Din, founded inConstantinople (todayIstanbul) byTaqi ad-Din Muhammad ibn Ma'ruf in 1577, was one of the largestastronomical observatories in the pre-modern world. However, it only existed for a few years and was destroyed in 1580.
In 1574,Murad III became theSultan of theOttoman Empire. The empire's chief astronomer,Taqi ad-Din, petitioned the Sultan to finance the building of a great observatory to rivalUlugh Beg'sSamarkand observatory. The Sultan approved, and construction was completed in 1577,[1] at nearly the same time asTycho Brahe's observatory atUraniborg.
This observatory consisted of two large structures perched on a hill overlooking the European section of Constantinople and offering a wide view of the night sky. Much like a modern institution, the main building was reserved for thelibrary and the living quarters of the staff, while the smaller building housed a collection of instruments built by Taqi ad-Din. These included a giant armillary sphere and an accurate mechanicalastronomical clock for measuring the position and speed of the planets. With these instruments, Taqi ad-Din had hoped to update the old astronomical tables describing the motion of the planets, sun, and moon.[1]
The observatory did not survive to advance the development of astronomy in the Muslim world. Within months of the observatory's completion, acomet with an enormous tail appeared in the sky and Sultan Murad III demanded a prognostication about it from his astronomer. "Working day and night without food and rest" Taqi ad-Din studiedthe comet and came up with the prediction that it was "an indication of well-being and splendor," and would mean a "conquest of Persia". Unfortunately, instead of splendor, a devastating plague followed in some parts of the empire, and several important persons died.[2] Astronomy was a respected and approved science among the Islamic clergy of the Ottoman Empire, yet the same could not be said with regard to astrology, a field which is considered to bedivination and thus againstsharia. In order to prevent its further use for astrological purposes, they successfully sought the observatory's destruction.[3][dubious –discuss] This happened just as the king of Denmark built an observatory forTycho Brahe that would pave the way forKepler's elucidation of the orbits of planets.[4]
Taqi ad-Din wrote an important treatise on astronomical instruments entitled theObservational Instruments of the Emperor's Catalogue, which describes the astronomical instruments used in the Constantinople observatory of Taqi ad-Din. These includedancient instruments such as thearmillary sphere, paralacticruler andastrolabe;medieval Muslim instruments such as the universal astrolabe,azimuthal andmural quadrants, andsextants; and several instruments he invented himself, including themushabbaha bi'l manattiq, a framed sextant with cords for the determination of theequinoxes similar to whatTycho Brahe later used, and a wooden quadrant for measuringazimuths and elevations. His most important astronomical instrument, however, is the "observational clock", which in hisIn the Nabk Tree of the Extremity of Thoughts, he describes as "a mechanicalclock with threedials which show thehours, theminutes, and theseconds. We divided each minute into five seconds." This was used for measuring theright ascension of thestars. This is considered one of the most important innovations in 16th century practical astronomy, as at the start of the century clocks were not accurate enough to be used for astronomical purposes.[5]
A "remarkably modern-looking" terrestrialglobe of theEarth, one of the earliest of its kind, was constructed byTaqi ad-Din at the Constantinople observatory of Taqi ad-Din.[6]
Taqi ad-Din made use of his new "observational clock" to produce azij (namedCulmination of Thoughts in the Kingdom of Rotating Spheres) more accurate than his predecessors,Tycho Brahe andNicolaus Copernicus. Taqi ad-Din was also the first astronomer to employ adecimal point notation in hisobservations rather than thesexagesimal fractions used by his contemporaries and predecessors. He also made use ofAl-Biruni's method of "three points observation". InThe Culmination of Thoughts in the Kingdom of Rotating Spheres, Taqi ad-Din described the three points as "two of them being in opposition in theecliptic and the third in any desired place on the ecliptic. He used this method to calculate theeccentricity of the Sun's orbit and the annual motion of theapogee, and so did Tycho Brahe and Copernicus shortly afterwards, though Taqi ad-Din's values were more accurate, due to his observational clock and other more accurate instruments.[5]