A total solar eclipse occurred at the Moon's ascending node of orbit on Wednesday, October 12, 1977, with a magnitude of 1.0269. 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 2.6 days before perigee (on October 15, 1977, at 10:00 UTC), the Moon's apparent diameter was larger.
Totality was visible in the Pacific Ocean, Colombia and Venezuela. A partial eclipse was visible for parts of North America, Central America, the Caribbean, and northern South America.
Observations The National Geographic Society funded an expedition by sea led by Jay Pasachoff from Williams College, Massachusetts to the northeast Pacific Ocean to observe the total eclipse. The team took images of the sky and corona during the totality phase as well as corona spectrum and infrared images.
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.
+October 12, 1977 Solar Eclipse Times Event Time (UTC) First Penumbral External Contact 1977 October 12 at 17:48:24.0 UTC First Umbral External Contact 1977 October 12 at 18:48:59.6 UTC First Central Line 1977 October 12 at 18:49:18.4 UTC First Umbral Internal Contact 1977 October 12 at 18:49:37.3 UTC First Penumbral Internal Contact 1977 October 12 at 20:01:41.4 UTC Equatorial Conjunction 1977 October 12 at 20:15:17.1 UTC Greatest Eclipse 1977 October 12 at 20:27:27.3 UTC Greatest Duration 1977 October 12 at 20:30:55.5 UTC Ecliptic Conjunction 1977 October 12 at 20:31:29.7 UTC Last Penumbral Internal Contact 1977 October 12 at 20:53:33.8 UTC Last Umbral Internal Contact 1977 October 12 at 22:05:23.4 UTC Last Central Line 1977 October 12 at 22:05:44.5 UTC Last Umbral External Contact 1977 October 12 at 22:06:05.6 UTC Last Penumbral External Contact 1977 October 12 at 23:06:31.5 UTC
+October 12, 1977 Solar Eclipse Parameters Parameter Value Eclipse Magnitude 1.02694 Eclipse Obscuration 1.05462 Gamma 0.38363 Sun Right Ascension 13h11m36.7s Sun Declination -07°35'30.0" Sun Semi-Diameter 16'01.8" Sun Equatorial Horizontal Parallax 08.8" Moon Right Ascension 13h12m03.0s Moon Declination -07°13'40.8" Moon Semi-Diameter 16'12.7" Moon Equatorial Horizontal Parallax 0°59'29.8" ΔT 48.3 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 September–October 1977 September 27Descending node (full moon) October 12Ascending node (new moon) Penumbral lunar eclipseLunar Saros 117 Total solar eclipseSolar Saros 143
Related eclipses Eclipses in 1977 A partial lunar eclipse on April 4. An annular solar eclipse on April 18. A penumbral lunar eclipse on September 27. A total solar eclipse on October 12.
Metonic Preceded by: Solar eclipse of December 24, 1973 Followed by: Solar eclipse of July 31, 1981
Tzolkinex Preceded by: Solar eclipse of August 31, 1970 Followed by: Solar eclipse of November 22, 1984
Half-Saros Preceded by: Lunar eclipse of October 6, 1968 Followed by: Lunar eclipse of October 17, 1986
Tritos Preceded by: Solar eclipse of November 12, 1966 Followed by: Solar eclipse of September 11, 1988
Solar Saros 143 Preceded by: Solar eclipse of October 2, 1959 Followed by: Solar eclipse of October 24, 1995
Inex Preceded by: Solar eclipse of November 1, 1948 Followed by: Solar eclipse of September 22, 2006
Triad Preceded by: Solar eclipse of December 12, 1890 Followed by: Solar eclipse of August 12, 2064
Solar eclipses of 1975–1978
Saros 143
Metonic series
Tritos series
Inex series
Notes
References