Istanbul museum showcases ancient celestial globe, 19th-century transit telescope
This globe made by Cafer Ibn-i Ömer Ibn Devletşah el-Kırmani between 1383-1384 has a full set of constellation figures with about 1,025 stars indicated by points punched in small silver inserts. (Photo courtesy of Rahmi M. Koç Museum)


Istanbul's Rahmi M. Koç Museum displays its collection of important observation and measurement tools such as a 14th-century celestial globe from the Islamic world and an Ottoman-Turkish astrolabe from 1671, shedding light on the history of science.

As Türkiye's first and only industrial museum reflecting developments in transportation, industry and communication history, Rahmi M. Koç Museum offers visitors the opportunity for astronomical exploration through its rich collection. Among the exhibited objects are 18th-century astronomical instruments, a quadrant from the 19th century, sextants, octants, solar system models, telescopes and various binoculars.

Celestial globe: Made by Cafer Ibn-i Ömer Ibn Devletşah el-Kırmani between 1383 and 1384, this globe is one of the oldest known celestial globes. With a diameter of 14 centimeters (5.51 inches), it depicts the shapes of constellations containing approximately a thousand stars, each represented by a silver dot at its center.

The interior display of the museum, Istanbul, Türkiye. (Photo courtesy of Rahmi M. Koç Museum)

Astrolabe: An Ottoman-Turkish astrolabe was made in 1671 by Ali al-Za’tari. Astrolabes are used to determine the positions of celestial bodies and to calculate time using pre-calculated positions of the sun and stars. In the medieval Islamic world, astrolabes were also used to determine prayer times in daily life.

Quadrant: Made of wood in 1866, this Ottoman-Turkish quadrant is adorned with rich floral decorations. Signed with the name "Ibrahim," this quadrant is used to measure the height (angular distance from the horizon) of a celestial object. The height of an object is measured by sighting along the edge of a quadrant (a quarter circle) and reading the angle it makes with the vertical line (plumb line).

Transit telescope: This transit telescope, branded Starke and Kammerer, was produced in Austria between 1871 and 1881. These telescopes utilize the Earth's rotation on its axis to bring objects into view.