An annular solar eclipse occurred at the Moon's descending node of orbit on Thursday, March 17, 1904,[1] [2] [3] [4] [5] with a magnitude of 0.9367. 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 only about 3 days after apogee (on March 14, 1904, at 6:00 UTC), the Moon's apparent diameter was smaller.[6]
The path of annularity covered southern German East Africa (now southern Tanzania), northeastern tip of Portuguese East Africa (now Mozambique), northern Grande Comore Island in French Comoros (now Comoros), southern British Seychelles (now Seychelles), British Mauritius (now Mauritius), most of the British Indian Ocean Territory (excluding the southern part of Diego Garcia), northwestern Sumatra in the Dutch East Indies (now Indonesia), southern Siam (now renamed as Thailand), French Indochina (the part now belonging to Cambodia, the southern tip of Laos and southern Vietnam, including the major city Phnom Penh, now capital of Cambodia), all of the Paracel Islands, the northern tip of the American Philippines (now Philippines) and Japanese islands of Iwo Jima, South Iwo Jima and Minamitorishima.
In addition, a partial solar eclipse was seen within a much larger area, including the eastern half of Africa, southern West Asia, southern Afghanistan, South Asia except the northernmost tip of British Raj (now the northernmost tip of Pakistan), most of China except the northwest border, Korean Peninsula, Japan, Southeast Asia, the extreme northern coast of Australia, northwestern Melanesia, central and western Micronesia, and southeastern Russian Empire.
N. Donitch of the Royal Russian Academy of Sciences (the predecessor of today's Russian Academy of Sciences) traveled to Phnom Penh (now capital of Cambodia) via Saigon (now Ho Chi Minh City, Vietnam) in French Indochina and made observations there. The weather was clear on the eclipse day, with only some fog in the morning. Donitch used a spectrometer and recorded changes in the temperature in about 2.5 hours, which dropped for about 3°C.[7]
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.[8]
| First Penumbral External Contact | 1904 March 17 at 02:36:24.1 UTC | |
| First Umbral External Contact | 1904 March 17 at 03:41:08.2 UTC | |
| First Central Line | 1904 March 17 at 03:43:53.3 UTC | |
| First Umbral Internal Contact | 1904 March 17 at 03:46:38.6 UTC | |
| First Penumbral Internal Contact | 1904 March 17 at 04:52:21.2 UTC | |
| Greatest Duration | 1904 March 17 at 05:37:38.0 UTC | |
| Ecliptic Conjunction | 1904 March 17 at 05:39:11.3 UTC | |
| Greatest Eclipse | 1904 March 17 at 05:40:44.1 UTC | |
| Equatorial Conjunction | 1904 March 17 at 05:45:36.1 UTC | |
| Last Penumbral Internal Contact | 1904 March 17 at 06:28:59.4 UTC | |
| Last Umbral Internal Contact | 1904 March 17 at 07:34:47.3 UTC | |
| Last Central Line | 1904 March 17 at 07:37:30.8 UTC | |
| Last Umbral External Contact | 1904 March 17 at 07:40:14.2 UTC | |
| Last Penumbral External Contact | 1904 March 17 at 08:44:57.8 UTC |
| Eclipse Magnitude | 0.93675 | |
| Eclipse Obscuration | 0.87751 | |
| Gamma | 0.12993 | |
| Sun Right Ascension | 23h46m07.3s | |
| Sun Declination | -01°30'13.7" | |
| Sun Semi-Diameter | 16'04.1" | |
| Sun Equatorial Horizontal Parallax | 08.8" | |
| Moon Right Ascension | 23h45m58.8s | |
| Moon Declination | -01°23'30.5" | |
| Moon Semi-Diameter | 14'49.6" | |
| Moon Equatorial Horizontal Parallax | 0°54'24.9" | |
| ΔT | 2.9 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. The first and last eclipse in this sequence is separated by one synodic month.