The constellation Pegasus

The constellation Pegasus ("The Winged or Flying Horse") as depicted in the influential star atlas of the Persian astronomer Abd al-Rahman al-Sufi (10th cent.). In this beautifully illustrated copy, made around 1435 for the Samarkand astronomer-ruler Ulugh Beg, the constellation is shown as depicted on a celestial globe (i.e. mirrored as seen in the night sky).

The brighter stars are labelled in Arabic which accurately translate the Greek names listed in the star catalogue of Claudius Ptolemy's Almagest (2nd cent.). The four brightest stars, forming the easily recognisable "Square of Pegasus" visible in the autumn and the winter night skies, are labelled Matn al-Faras ("The Horse's Back" = Alpha Pegasi), Mankib al-Faras ("The Horse's Shoulder" = Beta Pegasi), Surrat al-Faras ("The Horse's Navel" = Alpha Andromedae) and Jinah al-Faras ("The Horse's Wing" = Gamma Pegasi).

The names for these stars in common use in recent centuries, which were recently adopted by the IAU WGSN,are Markab (Alpha Pegasi), Scheat (Beta Pegasi), Alpheratz (Alpha Andromedae), and Algenib (Gamma Pegasi).

The modern constellation Pegasus also contains the star designated 51 Pegasi, which hosts the first exoplanet discovered (in 1995) around a solar-type star. As a result of the NameExoWorld contest organized by the IAU, the star is now named Helvetios (and the exoplanet, designated 51 Pegasi b, is named Dimidium).

The compass directions are labelled in red, i.e. the top is west, bottom is east, left is south and right is north.

Image details: BnF ms. Arabe 5036, fol. 93r.

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