Welcome to the homepage of the Solar Observation in Bulgaria - SOB

SOB is the solar physics project of the National Astronomical Observatory (NAO) Rozhen. The project is part of the research activities of the Department 'Sun and Solar System' at the Institute of Astronomy (IA) and NAO Rozhen, Bulgarian Academy of Sciences.

Astronomy Calendar of Celestial Events 2010

In all reports, times and dates are in standard time for Sofia, Bulgaria
Latitude:           42°41'05" N
Longitude:        23°19'10" E
Local Time = UT +   2:00 hours
Elevation:         560 meters
More reports generated by Astronomy Lab, marked as astron. lab
(corrected by daylight savings time or summer time).
Times are in 24 hour format.

Partial blue Moon eclipse on 31 Dec 2009

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Just before the end of 2009 we ware witness of the second full Moon of December named a Blue Moon. But only 3 hours before the New Year the Nature was present a follow phenomenon for us as a partial lunar eclipse. If we believe of superstitions or myths now is the moment to expect a lot of surprises from 2010.
 Partial Blue moon  eclipse

The Known Universe Scientifically Rendered For All to See

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The Known Universe Scientifically Rendered For All to See

After hovering over Mount Everest and the gorges that plunge to the Ganges, you are pulled through the Earth’s atmosphere to glimpse the inky black of space over Tibet’s high desert. So begins The Known Universe, a new film produced by the American Museum of Natural History that is part of a new exhibition, Visions of the Cosmos: From the Milky Ocean to an Evolving Universe, at the Rubin Museum of Art in New York City. 

Total solar eclipse on 22 July 2009

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 The research team of the Institute of Astronomy, Bulgarian Academy of Sciences realized observations of the total solar eclipse on 22 July 2009 form Tianhungping, China.

Unfortunately, the weather condition was not perfect time for observations and was impossible to receive good photographically information.


Main meteor showers for 2009

Main meteor showers for 2009

proton-proton chain

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p-p 01.jpg

The core makes about 2% of the Sun’s volume (core’s radius is ~1/4 Rסּ) but contains nearly half of its mass. The highest temperature is in the center ~1.55x107 and decreases outwards to 9.42x106 K. The high temperatures and densities provide conditions for the nuclear fusions that power the Sun. Most energy is provided from the three step process of hydrogen to helium conversion (proton-proton chain). A single proton-proton chain yields 26.73 MeV in gamma rays and ~0.5 MeV in two neutrinos.

Solar Structure

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Cross-section of the Sun (SOB)

This diagram shows main layers of a solar-type star. Using a neutral filter we can see from the Earth one perfect disk and this is the solar photosphere. Layers under the photosphere are invisible for us. With special instruments and filters there are possibilities to observe some phenomenon from the chromosphere (spicules, filaments, etc.). During total solar eclipses is possible to observe the solar corona.

Full circle halo

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Circle rainbow during the dayExtraordinary halo around the Sun was observed on 24 Apr 2009 from the Observatory Rozhen.
This full circle halo was visible during the day. I've never saw it before.
The phenomenon was visible for quiet some time – more than 1 hour.

A list of the papers by years published by members of the Department “Sun” (1984-2010)

Here is a list of the papers by years published by members of the Department “Sun” (1984-2010), as well as earlier solar publications made in the Institute of Astronomy and in Department “Astronomy” of the Faculty of Physics of Sofia University “St. Kliment Ohridski”. 

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