An annular solar eclipse occurred at the Moon's ascending node of orbit on Friday, May 20, 1966, with a magnitude of 0.9991. 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. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. The Moon's apparent diameter was near the average diameter because it occurred 6.8 days after apogee (on May 13, 1966, at 14:00 UTC) and 7.2 days before perigee (on May 27, 1966, at 15:00 UTC).
Annularity was visible from Guinea (including the capital city Conakry), Mali, Algeria, Libya, Greece, Turkey, the Soviet Union (today's Russia and Kazakhstan) and China. A partial eclipse was visible for parts of North Africa, Central Africa, Northeast Africa, Europe, West Asia, Central Asia, North Asia, and South Asia.
Observations During this eclipse, the apex of the moon's umbral cone was very close to the Earth's surface, and the magnitude was very large. The edges of the moon and the sun were very close to each other as seen from the Earth. Baily's beads on the lunar limb, which are usually only visible during a total solar eclipse, could also be seen. Therefore this eclipse was also an excellent opportunity to measure the size and shape of the Earth, as well as the mountains and valleys on the lunar limb. Many scientists observed the annular eclipse in Greece and Turkey, which are close to the location of maximum eclipse and have better observation conditions. The observation sites in Greece were mainly concentrated in Saronida and Anavyssos south of Athens, while those in Turkey were mainly concentrated in Ayvalik, across the sea facing the Greek island Lesbos.
Similar to the Baily's beads, the corona is generally only visible in a total solar eclipse. Because the magnitude of this annular eclipse was close to 1, some predicted that the corona would be visible. An observation team went to Lesbos Island but only saw the Baily's beads, not the corona.
Prior to it, the two hybrid solar eclipses of April 17, 1912 and April 28, 1930, and another annular solar eclipse of May 9, 1948 also belonging to Solar Saros 137, also occurred with a magnitude close to 1. Observations were made near Paris in France, Camptonville, California and Rebun Island in Japan respectively.
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.
+May 20, 1966 Solar Eclipse Times Event Time (UTC) First Penumbral External Contact 1966 May 20 at 06:50:51.2 UTC First Umbral External Contact 1966 May 20 at 07:54:07.8 UTC First Central Line 1966 May 20 at 07:54:41.4 UTC Greatest Duration 1966 May 20 at 07:54:41.4 UTC First Umbral Internal Contact 1966 May 20 at 07:55:14.9 UTC First Penumbral Internal Contact 1966 May 20 at 09:07:24.3 UTC Greatest Eclipse 1966 May 20 at 09:39:01.6 UTC Ecliptic Conjunction 1966 May 20 at 09:42:51.0 UTC Equatorial Conjunction 1966 May 20 at 09:51:45.8 UTC Last Penumbral Internal Contact 1966 May 20 at 10:10:21.8 UTC Last Umbral Internal Contact 1966 May 20 at 11:22:42.3 UTC Last Central Line 1966 May 20 at 11:23:12.9 UTC Last Umbral External Contact 1966 May 20 at 11:23:43.5 UTC Last Penumbral External Contact 1966 May 20 at 12:27:00.2 UTC
+May 20, 1966 Solar Eclipse Parameters Parameter Value Eclipse Magnitude 0.99915 Eclipse Obscuration 0.99830 Gamma 0.34672 Sun Right Ascension 03h46m47.1s Sun Declination +19°55'23.3" Sun Semi-Diameter 15'48.2" Sun Equatorial Horizontal Parallax 08.7" Moon Right Ascension 03h46m20.7s Moon Declination +20°14'08.1" Moon Semi-Diameter 15'33.4" Moon Equatorial Horizontal Parallax 0°57'05.7" ΔT 36.9 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 May 1966 May 4Descending node (full moon) May 20Ascending node (new moon) Penumbral lunar eclipseLunar Saros 111 Annular solar eclipseSolar Saros 137
Related eclipses Eclipses in 1966 A penumbral lunar eclipse on May 4. An annular solar eclipse on May 20. A penumbral lunar eclipse on October 29. A total solar eclipse on November 12.
Metonic Preceded by: Solar eclipse of July 31, 1962 Followed by: Solar eclipse of March 7, 1970
Tzolkinex Preceded by: Solar eclipse of April 8, 1959 Followed by: Solar eclipse of June 30, 1973
Half-Saros Preceded by: Lunar eclipse of May 13, 1957 Followed by: Lunar eclipse of May 25, 1975
Tritos Preceded by: Solar eclipse of June 20, 1955 Followed by: Solar eclipse of April 18, 1977
Solar Saros 137 Preceded by: Solar eclipse of May 9, 1948 Followed by: Solar eclipse of May 30, 1984
Inex Preceded by: Solar eclipse of June 8, 1937 Followed by: Solar eclipse of April 29, 1995
Triad Preceded by: Solar eclipse of July 19, 1879 Followed by: Solar eclipse of March 20, 2053
Solar eclipses of 1964–1967
Saros 137
Metonic series
Tritos series
Inex series
Notes
References