A total solar eclipse occurred at the Moon's ascending node of orbit on Tuesday, May 20, 1947,[1] with a magnitude of 1.0557. 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 1.8 days before perigee (on May 22, 1947, at 9:10 UTC), the Moon's apparent diameter was larger.[2]
Totality was visible from Chile including the capital city Santiago, Argentina, Paraguay, Brazil, Liberia, French West Africa (the parts now belonging to Ivory Coast and Benin), British Gold Coast (today's Ghana) including capital Accra, French Togoland (today's Togo) including capital Lomé, British Nigeria (today's Nigeria) including capital Lagos, French Cameroons (now belonging to Cameroon), French Equatorial Africa (the parts now belonging to Central African Republic and R. Congo), Belgian Congo (today's DR Congo), British Uganda (today's Uganda), British Tanganyika (now belonging to Tanzania), and British Kenya (today's Kenya). The southern part of Aconcagua, the highest mountain outside Asia, and Iguazu Falls, one of the largest waterfalls systems in the world, lay in the path of totality. A partial eclipse was visible for most of South America and Africa.
The Royal Astronomical Society of Canada sent a team to Araxa, Brazil. On the morning of the eclipse day, the sky was covered with clouds. Although a slight part of sunlight was seen through the gaps in the clouds around the first contact (the beginning of the partial phase), the weather did not improve after that. The eclipse ended at noon, and the sky began to clear up in the afternoon. The team documented changes in winds and luminance of the sky.[3] Australian radio astronomers originally planned to go to Brazil to make radio observations to promote the development of radio astronomy in Australia. However, the shipping of the equipments could only be made via London at that time, and it was not made before the eclipse in the end, so the plan was not successful. Another team from the Soviet Union successfully made radio observations in Brazil.[4]
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.[5]
| First Penumbral External Contact | 1947 May 20 at 11:11:14.5 UTC | |
| First Umbral External Contact | 1947 May 20 at 12:08:46.7 UTC | |
| First Central Line | 1947 May 20 at 12:09:53.9 UTC | |
| First Umbral Internal Contact | 1947 May 20 at 12:11:01.1 UTC | |
| First Penumbral Internal Contact | 1947 May 20 at 13:16:38.2 UTC | |
| Equatorial Conjunction | 1947 May 20 at 13:35:31.5 UTC | |
| Ecliptic Conjunction | 1947 May 20 at 13:44:07.5 UTC | |
| Greatest Eclipse | 1947 May 20 at 13:47:47.0 UTC | |
| Greatest Duration | 1947 May 20 at 13:54:23.9 UTC | |
| Last Penumbral Internal Contact | 1947 May 20 at 14:19:13.8 UTC | |
| Last Umbral Internal Contact | 1947 May 20 at 15:24:38.7 UTC | |
| Last Central Line | 1947 May 20 at 15:25:47.7 UTC | |
| Last Umbral External Contact | 1947 May 20 at 15:26:56.7 UTC | |
| Last Penumbral External Contact | 1947 May 20 at 16:24:20.8 UTC |
| Eclipse Magnitude | 1.05567 | |
| Eclipse Obscuration | 1.11445 | |
| Gamma | −0.35279 | |
| Sun Right Ascension | 03h45m52.5s | |
| Sun Declination | +19°52'36.9" | |
| Sun Semi-Diameter | 15'48.2" | |
| Sun Equatorial Horizontal Parallax | 08.7" | |
| Moon Right Ascension | 03h46m20.8s | |
| Moon Declination | +19°32'28.8" | |
| Moon Semi-Diameter | 16'25.3" | |
| Moon Equatorial Horizontal Parallax | 1°00'16.3" | |
| ΔT | 28.0 s |
See also: Eclipse cycle. 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.