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. Occurring about 3.7 days after perigee (on July 27, 1981, at 10:20 UTC), the Moon's apparent diameter was larger.
The moon's apparent diameter was 7 arcseconds larger than the February 4, 1981 annular solar eclipse.
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 lay in the path of totality. A partial eclipse was visible for parts of Northern Europe, Asia, Alaska, western Canada, and Greenland. 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.
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 altitudes 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.
Eclipse details Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the Moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.
+July 31, 1981 Solar Eclipse Times Event Time (UTC) First Penumbral External Contact 1981 July 31 at 01:12:08.0 UTC First Umbral External Contact 1981 July 31 at 02:18:14.0 UTC First Central Line 1981 July 31 at 02:18:40.7 UTC First Umbral Internal Contact 1981 July 31 at 02:19:07.5 UTC Equatorial Conjunction 1981 July 31 at 03:36:25.8 UTC Greatest Duration 1981 July 31 at 03:43:31.6 UTC Greatest Eclipse 1981 July 31 at 03:46:36.6 UTC Ecliptic Conjunction 1981 July 31 at 03:52:48.9 UTC Last Umbral Internal Contact 1981 July 31 at 05:14:16.1 UTC Last Central Line 1981 July 31 at 05:14:40.1 UTC Last Umbral External Contact 1981 July 31 at 05:15:04.1 UTC Last Penumbral External Contact 1981 July 31 at 06:21:15.5 UTC
+July 31, 1981 Solar Eclipse Parameters Parameter Value Eclipse Magnitude 1.02584 Eclipse Obscuration 1.05235 Gamma 0.57917 Sun Right Ascension 08h41m03.3s Sun Declination +18°18'24.9" Sun Semi-Diameter 15'45.4" Sun Equatorial Horizontal Parallax 08.7" Moon Right Ascension 08h41m26.2s Moon Declination +18°51'47.8" Moon Semi-Diameter 15'57.1" Moon Equatorial Horizontal Parallax 0°58'32.6" ΔT 51.8 s
Eclipse season
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.
+ Eclipse season of July 1981 July 17Descending node (full moon) July 31Ascending node (new moon) Partial lunar eclipseLunar Saros 119 Total solar eclipseSolar Saros 145
Related eclipses Eclipses in 1981 A penumbral lunar eclipse on January 20. An annular solar eclipse on February 4. A partial lunar eclipse on July 17. A total solar eclipse on July 31.
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
Solar eclipses of 1979–1982
Saros 145
Metonic series
Tritos series
Inex series
References
External links
Solar Corona Shape
Photos: Prof. Druckmüller's eclipse photography site: Solar eclipse of July 31, 1981 Prof. Druckmüller's eclipse photography site: Solar eclipse of July 31, 1981 (Fe XIV and Fe X images)