The Bulgarian scientists showed a strong interest in the total solar eclipse on August 11, 1999. The preparation for the eclipse and the eclipse observations were coordinated by the National Eclipse Committee with a chairman acad. D. Mishev and a secretary prof. V. Dermenjiev. The Committee’s main purpose was a selection and including into the National Eclipse Programme of detailed and various investigations of the Sun-Earth system in the frame of joint projects between the Institutes of Bulgarian Academy of Science, Sofia University and People Astronomical Observatories. Some foreign science and research teams took part in these programs: the Astronomical Observatory of Wroclaw University, Poland; IZMIRAN and GAIS; Rutherford Appleton Laboratory. The programs for the total eclipse were presented and discussed during the three consecutive JOSO annual sessions of Working Group 7 (Dermendjiev and Mishev, 1999).
In accordance with the National program for the total solar eclipse, 11 science-research programs have been implemented.
Five scientific programs have been related to the corona:
• Registration of Rapid Changes in the Visible Wavelength of the Solar Corona;
• Registration of Low-Excitation Emission Lines of the Solar Corona;
• Registration of the Outer Boundary of the Dust-free Zone of the Solar Corona;
• Polarimetry Researches of the Solar Corona;
• Photographic Study of the Solar Corona.
Six of the programs are related to the research of solar-terrestrial influences:
• Spectral components and colorimetric characteristic changes in the solar radiation;
• Investigation of the visible and infrared atmospheric radiation;
• Study of the ionosphere response;
• Research of the phenomenon “fleeting shadows”;
• Study of the atmosphere conditions and radiate characteristics of the Earth’s surface;
• Solar eclipse influence on some physiological factors.
The initial results have been reported in the Sixth National Conference on Solar-Terrestrial influence and The Annual JOSO’s meeting (Dermendjiev, 1999).