An annular solar eclipse occurred at the Moon's descending node of orbit on Saturday, March 17, 1923,[1] with a magnitude of 0.931. 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 1.7 days before apogee (on March 19, 1923, at 20:30 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible from Chile, Argentina, Falkland Islands including capital Stanley, Gough Island in Tristan da Cunha, South West Africa (today's Namibia), Bechuanaland Protectorate (today's Botswana, Southern Rhodesia (today's Zimbabwe) including capital Salisbury, Portuguese Mozambique (today's Mozambique), Nyasaland (today's Malawi), French Madagascar (the part now belonging to Madagascar, and the Islands of Juan de Nova and Tromelin). A partial eclipse was visible for parts of southern South America, Southern Africa, Central Africa, and Antarctica.
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.[3]
| First Penumbral External Contact | 1923 March 17 at 09:50:46.8 UTC | |
| First Umbral External Contact | 1923 March 17 at 11:02:32.4 UTC | |
| First Central Line | 1923 March 17 at 11:05:55.6 UTC | |
| First Umbral Internal Contact | 1923 March 17 at 11:09:20.9 UTC | |
| Equatorial Conjunction | 1923 March 17 at 12:24:30.3 UTC | |
| Greatest Duration | 1923 March 17 at 12:44:57.5 UTC | |
| Greatest Eclipse | 1923 March 17 at 12:44:57.7 UTC | |
| Ecliptic Conjunction | 1923 March 17 at 12:51:27.3 UTC | |
| Last Umbral Internal Contact | 1923 March 17 at 14:20:49.0 UTC | |
| Last Central Line | 1923 March 17 at 14:24:15.1 UTC | |
| Last Umbral External Contact | 1923 March 17 at 14:27:39.2 UTC | |
| Last Penumbral External Contact | 1923 March 17 at 15:39:20.9 UTC |
| Eclipse Magnitude | 0.93100 | |
| Eclipse Obscuration | 0.86676 | |
| Gamma | −0.54381 | |
| Sun Right Ascension | 23h44m59.2s | |
| Sun Declination | -01°37'34.5" | |
| Sun Semi-Diameter | 16'04.2" | |
| Sun Equatorial Horizontal Parallax | 08.8" | |
| Moon Right Ascension | 23h45m34.9s | |
| Moon Declination | -02°05'35.9" | |
| Moon Semi-Diameter | 14'46.5" | |
| Moon Equatorial Horizontal Parallax | 0°54'13.4" | |
| ΔT | 23.1 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.