İslâm Tarihinde Rasathaneler
Observatories in the History of Islam
Yazar: Bakkal, Ali
Dergi: Bilimname, Vol. 2019 No. 39, 2019
Anahtar kelimeler: Astronomi,Rasathane,Merâga Rasathanesi,Semerkant Rasathanesi,İstanbul Rasathanesi

İslâm tarihinde kurulan rasathanelerin en önemlileri Fahrüddevle (Rey) (994), Melikşâh (İsfahan) (1075), Merâga (1259), Semerkant (1408-1424 arası) ve İstanbul (1575-1580) rasathaneleridir. İslâm bilimi bu müesseselerde yapılan gözlemler sonucunda gelişti ve Batı’da Rönesans’ın temellerini oluşturdu. Ancak 1580 yılında İstanbul Rasathanesi’nin yıkılmasıyla, müslümanlar astronomide duraklama dönemine girerken, Avrupalılar teleskopun da icadıyla astronomiyi gün geçtikçe geliştirdiler. Rasathane-i Âmire’nin kurulmasıyla yeni bir başlangıç yapılmak istendiyse de bunda pek başarılı olunamadı. Bu makalede Emevîler’den Osmanlılar’ın yıkılışına kadar İslâm tarihinde kurulan rasathaneler tespit edilmiş ve bunlar hakkında kısa bilgi verilmiştir.Bu makalenin amacı İslâm tarihinde kurulan rasathaneleri kronolojik olarak tespit etmek ve bu müesseseleri temel özellikleri itibariyle tanıtmaktır. Bilindiği gibi İslam’dan önceki dönemlerde rasathane yoktu. Astronomik gözlemler genellikle nakledilebilir aletlerle yapılırdı. Müslümanlar, başlangıçta kabul ettikleri Batlamyus (ö. 168 yılı civarı) astronomi sisteminin bazı hatalar verdiğini görünce, bunları düzeltmek için uzun süre gözlem yapılması gerektiğine karar verdiler ve bunu gerçekleştirmek için rasathane kurdular. İslâm tarihinde ilk rasathanenin Emevîler döneminde Şam’da kurulduğuna dair bazı bilgiler varsa da, genel olarak araştırmacılar ilk rasathanenin Me’mun tarafından Bağdat’ta kurulan Şemmâsiye Rasathanesi olduğunu kabul ederler. Me’mun bir yıl sonra burada yapılanı gözlemlerin sağlamasını yapmak için Şam’da Kâsiyûn dağında ikinci bir rasathane kurdurmuştur. Bundan sonra rasathane kurmak İslâm devletlerinin geleneği haline gelmiş olup, Osmanlılar’ın sonuna kadar İslâm dünyasında elliye yakın rasathane kurulmuştur.

Although Indians, Egyptians, Babylonians and Greeks had made astronomical observations before Islam, these were not long-term observations at observatories. Establishing an observatory and observing it for many years is a Muslim tradition. Along with the translation movements, Muslims who adopted Ptolemy astronomy soon felt that this system had significant errors, and they felt the need to make long-term observations and, consequently, to establish observatories.Although there is some information in the history of Islam that the first observatory was established during the Umayyad period, this is not proven. According to the historians of science, the first observatory in Islamic history was the Semmâsa Observatory built in Baghdad by the Abbasid Caliph Me’mun. One year later, Me'mun had built the second observatory on the Qasiyûn Mountain in Damascus. After that, close to fifty observatories were established in each region of the Islamic geography with private and state support until the end of the Ottomans. The list of these observatories is as follows:Semmâsa Observatory (827), Qasiyûn Observatory (828), Private Observatory of Benî Mûsâ (840), Samerra Observatory, Special Observatory of Mâhânî (before 880), İbn Firnâs Special Observatory (274/887 before), Abu Hanî ed. -Dînevenî's Private Observatory (895), Battânî's Private Observatory, Ibn Emâcûr's Private Observatory (10th century), Rey Observatory (959), Rüknüddevle Observatory (947-977), Şîraz Observatory (978-998) ), Baghdad (Şerefüddevle) Observatory (988), Kaš Observatory (Private Observatory of Bîrûnî) (990-995), Private Observatory of Abu'l-Wafa al-Buzcânî, Private Observatories in Andalusia, Fahrüddevle (Rey) Observatory (994), Mukattam Observatory (Egypt) (975-996), Ibn Yunus' Private Observatory (before 1009), Hemedan Observatory (around 1023), Benî A'lem Observatory (1043), Yinânî Observatory (Damascus) (11) century, Melikşah (Isfahan) Observatory (1075), Cairo R (1120-1125), Seljuk Observatory (1130), Isbîliye Observatory (1195), Merâga Observatory (1259), Caca Bey (Kırşehir) Observatory (1272), Tabriz Observatory (1300), Samarkand Observatory (1408-1424), Bayezid Observatory (1447-1512), Trabzon Observatory, Istanbul Observatory (1575-1580), Delhi, Jaipur, Benares, Ujain (Ujjain) and Madura (India) Observatories, Yazd Observatory, Fez Observatory, Amire Observatory and Kandilli Observatory, Medina ObservatorySemmâsa and Qasiyûn Observatories are of great importance since they are the first. More observations of the moon and the sun were made at these two observatories. Although each observatory has a special importance, in terms of its features and scientific results, the observatories of Fahrüddevle (Rey) (994), Melikşâh (İsfahan) (1075), Merâga (1259), Samarkand (1408-1424) and Istanbul (1575-1580) have a distinct importance.The Fahrüddevli Observatory was a structure consisting of two parallel walls, 20 meters in width, 10 meters in height, 3,5 meters from each other. Inside this structure was a 20-meter-high sextant. With this sextant it was possible to calculate the height of the sun on the horizon, or how far away it was at its peak. Hucendi, who was the ruler of the observatory, also found that with the help of this sextant, the ecliptic (uptake) slope was continuously reduced.The Meliksah (Isfahan) Observatory was established to identify the shortcomings of the Yezdicerd calendar used in Iran at that time and to prepare a more robust calendar. 6-8 scientists were working at this observatory under the chairmanship of Omar Khayyam. As a result of the observations, instead of correcting the Yazdicerd calendar, a new calendar called Jalali calendar was prepared. This calendar contains more accurate information than the Gregorian calendar used today. For example, the Gregorian calendar made a mistake one day in 3330 years, while the Jalalî calendar made a mistake one day in 5000 years. In addition, as a result of observations made at the Melikşah Observatory, the delegation that prepared the Jalalî calendar prepared astronomical tables called Zîc-i Melikşâhî.Merâga Observatory is the first fully organized observatory in Islamic history. This observatory, built by the ruler of Ilhan Hülâgû in the city of Merâga to Nasîrüddîn-i Tûsî, was built on the basis of the Melikşah Observatory tradition. The observatory had a central tower with a diameter of 28 meters and had a large sextant with a radius of 10 to 12 meters. Outside the central tower, the observatory had five circular sections, a rectangular hall, library, conference room, workshop and many study rooms. At the observatory there were about fifteen mathematical and astronomical scholars, headed by Nasîdüddin-i Tûsî. At the observatory there were at least ten different observation instruments. It is noteworthy that the instruments used in the Merâga Observatory were excellent in comparison with the instruments used in European observatories in the 16th and 17th centuries. As a result of the observations made in this observatory, astronomical tables called Zîc-i İlhânî were prepared in 1271. The library within the observatory contained around four hundred thousand volumes of books. At first, the Astronomical Observatory, where astronomy and mathematics were taught, was a science academy and a university. The Samarkand Observatory was established by Uluğ Bey to correct the mistakes and deficiencies in Zîc-i İlhânî. The cylindrical building had a height of about 30 meters from the ground and a width of 46 meters. The studies carried out under the supervision of Gıyâseddin Cemşîd al-Qaşî, Kadızâde-i Rûmî and Ali Kuşçu scholars continued uninterruptedly for more than fifty years. As a result of the observations, astronomical tables called Zîc-i Uluğ were prepared. Zîc-i Uluğ Bey is an intermediate ring between the old astronomy and the new astronomy and is also an astronomy encyclopedia. In addition, solar, planet and comet observations were performed at this observatory by astronomers specialized in a specific program. The Samarkand Observatory has a very important place in the history of world astronomy with its special building built for astronomical observations, its large measuring instruments and its carefully arranged famous zic.The Istanbul Observatory, founded by Takıyyüddîn er-Râsıd, is almost the only observatory of the Ottoman Empire. At the same time, the instruments at the observatory, where twenty experts worked, were in full parallel with the observation tools at the Uranienburg Observatory (1576), which Tycho Brahe had established on the island of Hven in Sweden. After four to five years of activity, it collapsed. The demolition of the observatory had a negative impact on scientific studies in the Ottomans and the period of science was suspended.