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" at the Institute of Astronomy (IA) at the Bulgarian Academy of Sciences, which operates the NAO-Rozhen

Apparent solar diameter and Basic Heliographic Data 2010
The rotation axis of the Sun, as we know it today, was determined from the proper motion of sunspots by Carrington (1863). The solar axis is inclined toward the Ecliptic by an amount varying from +7o15’ to -7o15’. Furthermore, the position of solar axis is variable with respect to the north-south direction or respect to the great circle that passes through the celestial poles and the center of the Sun. This variation of the solar axis reaches the relatively large amount from +26o22’ to -26o22’. By table bellows we present day nottion B0 (heliographic latitude of the solar disk),
position angle of solar rotational axis from the north-south direction P0 and the longitude of center of solar disk L0.
The table data are calculated for 12:00 UT.
 

Astronomy Calendar of Celestial Events 2010
The Astronomy calendar includes data for some general celestial events during 2010. In all reports, times and dates are in standard time for Sofia, Bulgaria. More reports generated by Astronomy Lab 2 for Windows, marked on the page as astron. lab.  Hall information that shows fixed time (seasons, sunrise/set moonrise/set, planet ephemerides etc.) is corrected by daylight savings time or summer time. Time is in 24 hour format.
 
Sofia coordinates location:
Latitude: 42°41'05" N, Longitude: 23°19'10" E, Elevation: 560 meters

Local Time = UT + 2:00 hours

Partial blue Moon eclipse on 31 Dec 2009

Submitted by nikipetrov on 9 January, 2010 - 11:31
nikipetrov's picture
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

Submitted by admin on 21 December, 2009 - 14:29
admin's picture

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

Submitted by nikipetrov on 22 July, 2009 - 12:08
nikipetrov's picture

 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.

 

Galactic Center of Milky Way Rises over Texas Star Party

Submitted by admin on 18 June, 2009 - 09:40
admin's picture

Main meteor showers for 2009

Main meteor showers for 2009

proton-proton chain

Submitted by nikipetrov on 6 May, 2009 - 21:41
nikipetrov's picture
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

Submitted by nikipetrov on 29 April, 2009 - 07:54
nikipetrov's picture
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

Submitted by nikipetrov on 24 April, 2009 - 15:26
nikipetrov's picture

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.

Syndicate content