The Indian Space Research Organization has already sent up three rockets, and at least five others are scheduled for launch during the eclipse, its spokesman, S. Satish, told CNN. Astronomers term the Friday phenomenon an annular eclipse, when the moon covers the center of the sun and not its edges. The Indian rockets will record changes the eclipse causes in the lower and middle atmosphere as it races from Africa to Asia, he said. "The occurrence of (the) eclipse will result in a sudden cut-off of solar radiation. This affects the atmospheric structure and dynamics," the space agency said in a news release. "The uniqueness of this eclipse is that it occurs during the noontime, when the incoming solar radiation is in its maximum, (the) sun being at its zenith." Satish said one more rocket will take off on Saturday to probe the aftereffects of the celestial event. The annular eclipse of the sun will be visible Friday inside a 300-kilometer-wide (190-mile-wide) track that will traverse half of Earth, according to scientists. An annular eclipse is one that occurs when the moon is near the point in its orbit where it is farthest from Earth. Its disk then appears smaller than that of the sun, so it cannot block out the sun entirely as in a total eclipse. Most of India's eclipse probes are being launched from a space facility on the country's southern tip. India has an expansive space program -- the space research organization has more than 60 events that it lists as "milestones" since 1962-63, including the successful use of polar and geosynchronous satellite launch vehicles. In 2008, India launched its first unmanned mission to the moon, shortly after a Chinese astronaut took his country's first spacewalk. Some consider the two countries to be in a 21st century, Asian version of the 1960s space race between the United States and the Soviet Union. Radio contact with the Indian moon orbiter, which carried payloads from the United States, the European Union and Bulgaria, was abruptly lost in August of last year, 14 months before the mission was to end. But in its 312 days and more than 3,400 orbits around the moon, the vehicle had met most of its scientific objectives, according to the space agency. Earlier in 2009, the Indian government increased the federal budget for space research to around $1 billion from some $700 million, according to Satish. Source: CNN