Technical Parameters

National Astronomical Observatory – Rozhen

National Astronomical Observatory (NAO) – Rozhen is situated in the Rhodope Mountains at 1750 m altitude and coordinates:

longitude: 1^h 38^m 58^s and latitude: 41° 41′ 48”.

The astronomical observatory is the biggest one-time Bulgarian investment in scientific infrastructure and a leading astronomical center in the South-East Europe. The 2-m RCC telescope of Rozhen Observatory is equipped with four new professional CCD cameras, coudé and éshelle spectrographs, a two-channel focal reducer, broad band and interference set of filters.

Observations with the focal reducer and in direct RC focus are carried out with ANDOR iKon-L BEX2-DD and ANDOR iKon-L E2V 42-40 CCD cameras (2048×2048 pixels, 13.5×13.5 μm size). The coudé-spectrograph of the 2-m RCC telescope at NAO – Rozhen is a powerful instrument that allows obtaining of stellar spectra with a high resolution, “signal-to-noise” ratio of about 1000, and to measure velocities in space with an accuracy of 500 m/s. The coudé-spectrograph is equipped with ANDOR Newton 940 CCD camera (2048×512 pixels, 13.5×13.5 μm size). The éshelle-spectrograph is a cross-dispersed, bench-mounted, fiber-fed instrument giving a resolution from ∼30000 to∼45000. The spectral range obtained in one single image is from 3900 to 9000 Å. The spectrograph is equipped with ANDOR iKon-L BEX2-DD CCD camera (2048×2048 pixels, 13.5×13.5 mm size).

NAO – Rozhen has at its disposal and two small telescopes for optical observations: the 50/70 cm Schmidt telescope and 60 cm Cassegrain telescope. Both telescopes are equipped at present with CCD cameras with thermo-electric cooling: FLI PL 9000 (3056×3056 pixels, 12×12 μm size) at the Cassegrain telescope and FLI PL 16803 (4096×4096 pixels, 9×9 μm size) at the Schmidt telescope. The relatively big field of observation makes the telescopes suitable for photometry of variable and fast moving objects, as well as of nearby galaxies. From 2005 NAO – Rozhen has also a 15 cm Lyot-coronagraph with H-alpha filter, designed for observations of quiescent, eruptive, and active prominences in the low solar corona; and a solar refractor, which is in preparation for observations in white-light and H-alpha line (the solar activity in the photosphere and chromosphere). A center for visitors, equipped with a 18 cm telescope, conference room and small museum, are situated in NAO – Rozhen, too.

Astronomical Observatory Belogradchik

The Astronomical Observatory Belogradchik (AOB) was built near the Belogradchik citadel at 610 m altitude and coordinates:

longitude 1^h 30^m 41^s and latitude 43° 37′ 22”

In 1965 a 60 cm Cassegrain telescope for professional research in astrophysics was ordered in Carl Zeiss Jena. For a decade this was the largest professional telescope in Bulgaria. Currently two main modes of astronomical observations are carried out at 60 cm Cassegrain telescope in AOB: with FLI PL 9000 CCD camera (3056×3056 pixels, 12×12 μm size) and with a fully computer controlled single channel photometer.

In 2019, we are planning to buy new CCD cameras for all small telescopes in NAO-Rozhen and AO Belogradchik.