The Largest Astronomical Observatory

On 13 March 1981, the Rozhen National Astronomical Observatory (abbreviated as NAO Rozhen) officially opened its doors, becoming a fundamental part of Bulgaria's scientific infrastructure. Its history, however, began in September 1979, when regular observations under a variety of scientific programmes commenced. Situated in the Rhodope Mountains on Sveti Duh Peak, near Chepelare, it is the largest astronomical observatory not only in Bulgaria, but also in south-eastern Europe and on the Balkan Peninsula.

The observatory is run by the Institute of Astronomy at the Bulgarian Academy of Sciences and represents a substantial investment in science: more than 12 million leva, making it one of the country's largest investments in scientific infrastructure. Its six telescopes include a versatile 2-metre Ritchey–Chrétien–Coudé (RCC) reflector made by Carl Zeiss Jena, a 50/70 cm Schmidt telescope, a 60 cm Cassegrain, a 15 cm solar coronagraph, a 30 cm MEADE and an 18 cm meniscus-Cassegrain.

The observatory provides opportunities for observations across a broad range of astronomical and astrophysical research, from studying the dynamics and physics of bodies in the Solar System to extragalactic research, including asteroids, comets, stellar spectra, star clusters, galaxies and quasars.

The Rozhen National Astronomical Observatory participates in various projects, including the creation of a network of small, remotely controlled and robotic telescopes in Bulgaria, known as SMARTNET. Its scientific achievements include the discovery of the first extrasolar planet, WASP-3c, on 10 July 2010.