Solar eclipse of July 31, 1981

A total solar eclipse occurred at the Moon's ascending node of orbit on Friday, July 31, 1981, with a magnitude of 1.0258. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. The continental path of totality fell entirely within the Soviet Union, belonging to Georgia, Kazakhstan and Russia today. The southern part of Mount Elbrus, the highest mountain in Europe, also lies in the path of totality. Occurring only 3.8 days after perigee (on July 27, 1981), the Moon's apparent diameter was larger. With a path width of 107.8 km (66.984 mi, or 353,674.541 feet), this total solar eclipse had an average path.

The eclipse was mostly seen on July 31, 1981, except for Alaska, northwestern Canada and Northwestern Hawaiian Islands, where a partial eclipse was seen on July 30 local time, and northern Greenland, where a partial eclipse started on July 30, passing midnight and ended on July 31 due to the midnight sun.

It was the 20th eclipse of the 145th Saros cycle, which began with a partial eclipse on January 4, 1639 and will conclude with a partial eclipse on April 17, 3009.

The moon's apparent diameter was 7 arcseconds larger than the February 4, 1981 annular solar eclipse.

Observations
Scientists from the High Altitude Observatory of National Center for Atmospheric Research, E. O. Hulburt Center for Space Research of the United States Naval Research Laboratory and the Academy of Sciences of the Soviet Union made studies to the high altitues of corona during the eclipse. A joint U.S.-Soviet observation team went to Bratsk, Irkutsk Oblast, Soviet Union. Scientists studied the three-dimensional structure of the corona based on coronagraph observations, images of the corona taken in Bratsk, and observations made from Solwind / P78-1 satellite.

Eclipses in 1981

 * A penumbral lunar eclipse on January 20, 1981.
 * An annular solar eclipse on February 4, 1981.
 * A partial lunar eclipse on July 17, 1981.
 * A total solar eclipse on July 31, 1981.

Metonic

 * Preceded by: Solar eclipse of October 12, 1977
 * Followed by: Solar eclipse of May 19, 1985

Tzolkinex

 * Preceded by: Solar eclipse of June 20, 1974
 * Followed by: Solar eclipse of September 11, 1988

Half-Saros

 * Preceded by: Lunar eclipse of July 26, 1972
 * Followed by: Lunar eclipse of August 6, 1990

Tritos

 * Preceded by: Solar eclipse of August 31, 1970
 * Followed by: Solar eclipse of June 30, 1992

Solar Saros 145

 * Preceded by: Solar eclipse of July 20, 1963
 * Followed by: Solar eclipse of August 11, 1999

Inex

 * Preceded by: Solar eclipse of August 20, 1952
 * Followed by: Solar eclipse of July 11, 2010

Triad

 * Preceded by: Solar eclipse of September 29, 1894
 * Followed by: Solar eclipse of May 31, 2068