site.btaUPDATED Bulgarian Astronomers Go to Mexico in April to Observe Total Solar Eclipse

A team of astronomers from the Institute of Astronomy with the National Astronomical Observatory (NAO) at the Bulgarian Academy of Sciences (BAS) will leave in April on an expedition to Mexico, where they will observe a total solar eclipse on April 8, Nikola Petrov, director of the Rozhen National Astronomical Observatory, who will also be part of the team, told BTA. Total solar eclipses are important for astronomy because during them it is possible to observe the solar corona in detail from Earth and practically at great distances from the Sun, Petrov said. He specified that the next total solar eclipse, which could be observed from the territory of Bulgaria, will be on September 3, 2081.

Bulgarian astronomers will observe the phenomenon from an area about 300 km northwest of Monterrey. The solar corona for each eclipse is unique in terms of being determined by solar activity, and there cannot be the same solar activity during different eclipses, the astronomer said. He added that the Bulgarian four-member team has set itself the task of carrying out several observational tasks.   

One of the main tasks of the team of Bulgarian astronomers in Mexico is based on polarization observations. These observations are related to determining the electron density distribution of the solar corona. 

Another possible task during the solar eclipse, according to Petrov, is to look for the nearest boundary to which neutral dust, which is a constituent of the solar system's interplanetary space, can be observed.  The scientific interest of the expedition participants in this task is focused on the observation of neutral dust sublimation processes. Reaching a sufficiently close distance to the Sun, under the influence of solar radiation, neutral dust changes from a solid to a gaseous state, i.e. a sublimation process takes place. The time during which this dust is heated and sublimated happens so that it emits a faint light, explains the director of the Rozhen Observatory.  According to him, this observational experiment will be carried out with the help of specific filters that can be used to observe precisely the glow in a certain wavelength of the electromagnetic spectrum and thus register the limits of the existence of this neutral dust.  

Another task of the expedition involves determining the fine structure of the solar corona in white light, i.e. using neutral density filters during a total solar eclipse. This will allow to estimate different magnetic structures, distributed in height, depending on local active solar formations. 

Such expeditions of Bulgarian astronomers to distant observing sites have become possible in the last four years thanks to projects at the Education Ministry under the Scientific Research Fund, Petrov said.  After the eclipse observations, the Bulgarian team will take part in a scientific conference in Monterrey between April 9 and 13.