Astronomy in the Islamic world

The manuscript collection in the archives of Istanbul's Kandilli Observatory sheds light on the astronomy, mathematics and geography of the Islamic world.

Astronomy in the Islamic world

Human beings have enjoyed observing the skies from time immemorial, developing calendars, making navigational maps, and ordering their lives by the seasons based on their keen observations. Indeed, throughout history attempts have been made to establish links between fate and fortune and the positions of the heavenly bodies.

On the Islamic Lunar calendar that was adopted with the inception of the religion, all the holy days and times of worship are determined by the position in the sky of the sun and the moon. Among the Ottomans and in the Islamic countries in general, astrology, astronomy and mathematics formed an intersecting area of investigation for men of science and religion alike, and instruments were invented and experiments conducted using new methods of observation and calculation.


Islamic astronomy, whose history is claimed in many sources to have begun in the 800's, is said to be based on the translation from the Sanskrit of the Sindhanta and of Ptolemy's Almagest (Mathematical Suntax) from the Greek. For a long time the fundamental purpose of the Islamic observatories was to construct the 'zic's or astronomical tables needed for making a calendar and to correct the older tables. Observation got under way with the founding of observatories during the reign of Mamun (813-833) in the Abbasid period when original treatises were produced in the field of astronomy. Among the scientists making the observations were al-Khwarazmî (d. ca. 850), the creator of algebra, and Habesh al-Hasîb (d. 840).

A number of observatories were founded and observations made during the periods of the Buwayhids, the Fatimids, the Seljuks, the Umayyads of Spain, the Ilkhanids and the Timurids as the science of astronomy continued to develop and new books were written. Among such studies were astronomy, observations of the sun and moon, and measurement of the latitude and longitude of the various cities according to the position of the heavenly bodies since this was important for determining the direction of Mecca for prayer.

The planets are also known to have been observed using the sensitive instruments at the Ibn-i Sina Observatory, which was founded some time later.

The observatory founded at Samarkand by Uluğ Bey in 1420-21 has a special place among Islamic observatories. Famous scientists of the day such as Gıyaseddin, Kadızade Rumi and Ali Kuşçu all worked under the direction of Uluğ Bey here, where observations for a long time were conducted using a meridian instrument.


The first observatory in the Ottoman world was the Istanbul Observatory set up by Takiyeddin. Founded at the behest of Murad III, it was razed again on the sultan's command when the Sheikh-ul-Islam of the time claimed that observations could bring misfortune. The second observatory, the Imperial Observatory, which started out in an apartment building on Istiklal Avenue in 1868, met the same fate as the first observatory when it destroyed in the uprising of 31 March 1909.

The new government formed after the rising appointed Fatin Gökmen (1878-1955) director of the Imperial Observatory and charged him with finding a location for the new building. Gökmen decided on İcadiye Hill on the Bosphorus at Kandilli, where the present observatory still stands, and work commenced there in 1911. When the offices of chief astronomer and mosque timekeeper were abolished in 1926, the observatory took over the task of calculating the Islamic calendar.

Attached to Boğaziçi University in 1982, the observatory was renamed the Kandilli Observatory and Earthquake Research Institute. During his term as director, Gökmen amassed a wealth of documents relating to the history of astronomy, mathematics and geography as well as manuscripts - either originals or translations, or compiled by the chief astronomer of their time- and left behind a valuable collection.


The oldest of the Ottoman State calendars among these manuscripts dates to 1444. Such calendars were drawn up every year in two parts, the annual calendar (takvim-i sal) starting from Nevruz (the first day of the year) and the calendar of predictions (ahkâm-ı sal). It is thought that these calendars were in the beginning put together by astronomers outside the palace and then submitted to it. Then, from the 16th century on, calendars were compiled by the chief astronomer, an official employee of the Ottoman State system, and presented to the highest men of state, namely the sultan and the grand vizier.

The first part of these generally two-part calendars included historical and astronomical information. The earliest calendars, for example, contain chronological lists of the prophets and their successors going back to Adam, as well as the Seljuk, Karamanid and Ottoman rulers, historical information, astronomical and astrological calculations. These were followed by 'signs' relating the month of the year and the day of the month; predictions based on the Sun, Moon, stars and seasons, interpretations of dreams, and even lists of foods and beverages appropriate to the time of year. The second part was the actual calendar, which generally took the form of fourteen page tables.


The most important extant observatory collection of such studies can be found today in the archives of the Boğaziçi University Kandilli Observatory and Earthquake Research Institute. The efforts initiated some time ago to bring this most important collection of the Islamic world to the light of day have recently borne fruit.

The calendars, astronomical yearbooks, and calendars of predictions compiled by the chief Ottoman astronomers in the one and only such collection in Turkey, which was started by the founder, Mehmed Fatin Gökmen, of the Kandilli Observatory, or, as it was originally known, the Imperial Observatory, have now been made available to historians of science in a catalogue. The Arabic, Persian and Ottoman originals of this collection of manuscripts, consisting of 1340 works in 828 volumes, were examined individually and organized by Prof. Dr. Günay Kut, founding chairman of the University's Department of Turkish Language and Literature, and published in the form of a book, Kandilli Observatory Manuscripts, by the Boğaziçi University Publishing House with the support of the Elginkan Foundation.

This study of Turkey's only collection of astronomical manuscripts contains examples of everything from the oldest Ottoman calendars to 'ahkâms' (predictions of the future based on the position of the heavenly bodies) and horoscopes. Including some rare and unique specimens and some very old dated copies, this collection of manuscript works is considered one of a few of its kind in the whole world.


Güncelleme Tarihi: 25 Temmuz 2007, 15:00