A total solar eclipse occurred at the Moon's ascending node of orbit on Sunday, September 21, 1941,[1] with a magnitude of 1.0379. 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 2.25 days before perigee (on September 23, 1941, at 10:40 UTC), the Moon's apparent diameter was larger.[2]
The path of totality crossed the Soviet Union (today's Russia, Kazakhstan and Kyrgyzstan), China, Taiwan, Okinawa Prefecture and South Seas Mandate (the parts now belonging to Northern Mariana and Marshall Islands) in Japan, and ended in the Pacific Ocean. A partial eclipse was visible for most of Asia, Northern Australia, and northern Oceania.
The Chinese Solar Eclipse Observation Committee sent two teams - one led by Zhang Yuzhe and Gao Lu to the Taiyue Temple in Lintao County, Gansu,[3] [4] and the other to Chong'an County (now Wuyishan City), Fujian.[5] The Lintao team started from Kunming, where a number of universities and institutes of higher education were evacuated during the war, on June 30, 1941, and arrived in Lintao on August 13. They traveled by car for a total of 3,200 kilometres and made science popularization speeches along the way.[3]
China was under the rule of the Republic of China and the eclipse occurred during the Second Sino-Japanese War. An artillery regiment was stationed near Lintao, and 20 fighter jets were stationed at Lanzhou Airport ready to intercept Japanese planes. The foggy weather in Lintao suddenly cleared up during the eclipse, making the observation successful. The solar chromosphere spectrum, a movie of the process of the eclipse and three corona images were taken. The brightness of the corona was measured to be 0.37 times that of the full moon. In Chong'an, the cloudy weather resulted in poor results of astronomical observations, but data of the change in Earth's magnetic field during the total phase was still measured.[5]
In November 1934, astronomer organized the Chinese Solar Eclipse Observation Committee to prepare for observations of the solar eclipse of June 19, 1936 and this eclipse in 1941.[6] [3] Due to the Soviet-German War and the Second Sino-Japanese War, European and American astronomers did not make field observations in the Soviet Union and China.[7]
Several universities in Japan made observations in Ishigaki Island in Okinawa, Pengjia Islet in Taiwan under Japanese rule, and Chinese sites including Dongyin Island in Fujian, Nanchang in Jiangxi, in Xianning, Hubei, in Jiayu, Hubei, and Hankou (now in Wuhan). Among them, Ishigaki Island had the sunniest weather and the most successful observation results. Results were poor due to thick clouds in Heshengqiao and Yanzhou where teams of Tokyo Imperial University, Kyoto Imperial University, and Tohoku Imperial University went.[8]
The Academy of Sciences of the Soviet Union began preparations in 1939. It was originally planned to involve 28 agencies, but due to the outbreak of World War II, only 7 observation teams were formed. The observation sites were Almaty and Kyzylorda in present-day Kazakhstan. The weather was good in Almaty with many observation results, while there were some clouds in Kyzylorda but several image were still taken.[9] European and American astronomers did not went to the Soviet Union due to the war.[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.[10]
| First Penumbral External Contact | 1941 September 21 at 01:58:50.4 UTC | |
| First Umbral External Contact | 1941 September 21 at 02:59:55.7 UTC | |
| First Central Line | 1941 September 21 at 03:00:37.1 UTC | |
| First Umbral Internal Contact | 1941 September 21 at 03:01:18.4 UTC | |
| Equatorial Conjunction | 1941 September 21 at 04:18:15.8 UTC | |
| Greatest Eclipse | 1941 September 21 at 04:34:02.9 UTC | |
| Greatest Duration | 1941 September 21 at 04:35:22.1 UTC | |
| Ecliptic Conjunction | 1941 September 21 at 04:38:53.8 UTC | |
| Last Umbral Internal Contact | 1941 September 21 at 06:06:56.6 UTC | |
| Last Central Line | 1941 September 21 at 06:07:40.0 UTC | |
| Last Umbral External Contact | 1941 September 21 at 06:08:23.3 UTC | |
| Last Penumbral External Contact | 1941 September 21 at 07:09:18.6 UTC |
| Eclipse Magnitude | 1.03791 | |
| Eclipse Obscuration | 1.07725 | |
| Gamma | 0.46494 | |
| Sun Right Ascension | 11h51m55.1s | |
| Sun Declination | +00°52'33.2" | |
| Sun Semi-Diameter | 15'55.9" | |
| Sun Equatorial Horizontal Parallax | 08.8" | |
| Moon Right Ascension | 11h52m29.0s | |
| Moon Declination | +01°18'57.7" | |
| Moon Semi-Diameter | 16'17.7" | |
| Moon Equatorial Horizontal Parallax | 0°59'48.1" | |
| ΔT | 25.2 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.