An annular solar eclipse occurred at the Moon's descending node of orbit on Monday, April 18, 1977, with a magnitude of 0.9449. 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. Occurring about 3.1 days before apogee (on April 21, 1977, at 13:00 UTC), the Moon's apparent diameter was smaller.
Annularity was visible in South West Africa (today's Namibia), Angola, Zambia, southeastern Zaire (today's Democratic Republic of Congo), northern Malawi, Tanzania, Seychelles and the whole British Indian Ocean Territory. A partial eclipse was visible for parts of eastern Brazil, Southern Africa, Central Africa, East Africa, Antarctica, the Middle East, and South Asia.
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.
+April 18, 1977 Solar Eclipse Times Event Time (UTC) First Penumbral External Contact 1977 April 18 at 07:33:32.8 UTC First Umbral External Contact 1977 April 18 at 08:41:17.9 UTC First Central Line 1977 April 18 at 08:43:51.9 UTC First Umbral Internal Contact 1977 April 18 at 08:46:26.6 UTC First Penumbral Internal Contact 1977 April 18 at 10:12:31.9 UTC Equatorial Conjunction 1977 April 18 at 10:18:48.0 UTC Greatest Eclipse 1977 April 18 at 10:31:29.9 UTC Ecliptic Conjunction 1977 April 18 at 10:36:13.6 UTC Greatest Duration 1977 April 18 at 10:40:30.0 UTC Last Penumbral Internal Contact 1977 April 18 at 10:50:48.6 UTC Last Umbral Internal Contact 1977 April 18 at 12:16:41.3 UTC Last Central Line 1977 April 18 at 12:19:17.4 UTC Last Umbral External Contact 1977 April 18 at 12:21:52.9 UTC Last Penumbral External Contact 1977 April 18 at 13:29:36.4 UTC
+April 18, 1977 Solar Eclipse Parameters Parameter Value Eclipse Magnitude 0.94492 Eclipse Obscuration 0.89288 Gamma −0.39903 Sun Right Ascension 01h45m03.2s Sun Declination +10°51'37.2" Sun Semi-Diameter 15'55.5" Sun Equatorial Horizontal Parallax 08.8" Moon Right Ascension 01h45m26.3s Moon Declination +10°30'41.9" Moon Semi-Diameter 14'50.4" Moon Equatorial Horizontal Parallax 0°54'28.0" ΔT 47.8 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 April 1977 April 4Ascending node (full moon) April 18Descending node (new moon) Partial lunar eclipseLunar Saros 112 Annular solar eclipseSolar Saros 138
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 June 30, 1973 Followed by: Solar eclipse of February 4, 1981
Tzolkinex Preceded by: Solar eclipse of March 7, 1970 Followed by: Solar eclipse of May 30, 1984
Half-Saros Preceded by: Lunar eclipse of April 13, 1968 Followed by: Lunar eclipse of April 24, 1986
Tritos Preceded by: Solar eclipse of May 20, 1966 Followed by: Solar eclipse of March 18, 1988
Solar Saros 138 Preceded by: Solar eclipse of April 8, 1959 Followed by: Solar eclipse of April 29, 1995
Inex Preceded by: Solar eclipse of May 9, 1948 Followed by: Solar eclipse of March 29, 2006
Triad Preceded by: Solar eclipse of June 17, 1890 Followed by: Solar eclipse of February 17, 2064
Solar eclipses of 1975–1978
Saros 138
Metonic series
Tritos series
Inex series
Notes
References