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.

Sunspots observations 03-09 August 2011

Sunspot observations during the summer astronomical school, 3rd - 9th August 2011, NAO Rozhen. The animated picture presents the movement of the sunspots (active regions 1260, 1261 and 1263) across the solar disc for 6 days.


Partial Solar eclipse on 01 June 2011

Partial Solar eclipse on 01 June 2011
Sun rise: 02:52 UT
Sun set: 17:58 UT
First contact:                                 19:25 UT
Time of maximum eclipse:        21:16 UT
Last contact:                                 23:07 UT

Mercury: The Key to Terrestrial Planet Evolution

The spacecraft MESSENGER obtained first images of Mercury, the planet closest to the Sun.
More information.

Why was the site down

 A few days ago the site (the entire domain in fact)  went off. We are back now, a simple administrative issue caused a delay in the domain renewal.

Super Moon on March 19, 2011

Perhaps the most famous celestial body in the night sky is the Moon. The moon is our natural satellite of Earth and it plays an important role in the life of our planet. There would hardly have been conditions for the existence of complex forms of life on Earth if the moon had not existed.It is stabilizing the movement of Earth around its axis, which is due to well-known terrestrial seasons. If we were living without our Moon, the Earth would probably be reversed uncontrollably around its solar orbit. This will lead to spontaneous and rapid changes of climates and we would not exist today as a human civilization. Perhaps this is why Mars is not inhabited by humanoids - the moons of Mars cannot stabilize rotation of the planet around its axis. We cannot deny that the world is full of strange and random phenomena. Only very slight modifications of any of them would have turned our notions about the world beyond recognition. If the moon did not exist –   we may would not be on the Earth. If the moon is farther away from its current position, it would never have enjoyed a total solar eclipse. Probably we still would not know of the existence of the solar corona. Moon rotates at the same speed as the speed and rotation around the Earth; from Earth we only see one side of the moon. Figure 1 presents some basic data about the Moon and Earth graphically.

Sunspot active region 1158

The last three days we are observing growth of a large active region (1158). Near to center of the visible solar disk and more than 10 times Earth’s diameter, this sunspot group is able to produce a "perfect" solar storm.

Partial solar eclipse on January 4, 2011 from NAO Rozhen

The partial solar eclipse on January 4, 2011 was observed through clouds and during snowfall. Unfortunately, it was not possible to shoot all phases of the eclipse. Below are presented images of the moments in which the cut solar disk was visible in the sky. The images show almost the  maximum phase of the eclipse for the territory of Bulgaria (National Observatory Rozhen).

10:05:38 local time (UT+2)

Partial solar eclipse on 4 January 2011

Partial solar eclipse on 4 January 2011 will be visible from Europe, North Africa and East Asia. Eclipse will be visible from the whole territory of Bulgaria with a maximum coverage of the solar disk of about 72%. Eclipse starts at 9:03 local time in Sofia, the maximum phase of the eclipse will occur at 10:27 hours and will end at 12:03 when the lunar disk will completely leave the sun.

This partial eclipse is the first solar eclipse of 2011. Is still three, but invisible to the territory of Bulgaria. More information about the next eclipses can be found in astronomical calendar on this web page.
Different phases of the eclipse are shown in the figure below.


Astronomy Calendar of Celestial Events 2011

Astronomy Calendar of Celestial Events 2011
The Astronomy calendar includes data for some general celestial events during 2011. 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. In all reports, times and dates are in standard time for Sofia, Bulgaria
or explicit is written Universal Time (UT). Times are in 24 hour format.

Quadrantids meteor shower 2011

nikipetrov's picture
The night on January 3th, 2011 Quadrantids meteor shower is at it's maximum. The Quadrantids are an above average shower, with about 80 meteors per hour at their peak. Best viewing will be from a dark location after midnight. Look for meteors radiating from the constellation Bootes. For Bulgaria the constellation Bootes on Jun 3th is visible after midnight in North-East direction on the horizon (Fig. below). Quadrantids are bright, blue and enter into the Earth atmosphere fast. Themselves speed is about 41 km/s.
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