| Solar eclipse of May 9, 1948 | |
|---|---|
 Map | |
| Type of eclipse | |
| Nature | Annular |
| Gamma | 0.4133 |
| Magnitude | 0.9999 |
| Maximum eclipse | |
| Duration | 0 s (0 min 0 s) |
| Coordinates | 39°48′N 131°12′E / 39.8°N 131.2°E / 39.8; 131.2 |
| Times (UTC) | |
| Greatest eclipse | 2:26:04 |
| References | |
| Saros | 137 (32 of 70) |
| Catalog # (SE5000) | 9394 |
An annular solar eclipse occurred at the Moon's ascending node of orbit on Sunday, May 9, 1948, with a magnitude of 0.9999. 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. Annularity was visible from Car Nicobar, the northernmost of the Nicobar Islands, and Burma, Siam (now renamed to Thailand) including Bangkok, French Indochina (the part now belonging to Laos), North Vietnam (now belonging to Vietnam), China, South Korea, Rebun IslandinJapan, Kuril Islands in the Soviet Union (now belonging to Russia) on May 9, and Alaska on May 8. It was the first central solar eclipse visible from Bangkok from 1948 to 1958, where it is rare for a large city to witness 4 central solar eclipses in 10 years. The moon's apparent diameter was only 0.006% smaller than the Sun's, so this was an annular solar eclipse that occurred on May 9, 1948. Occurring 7.1 days after apogee (on May 2, 1948) and 6.6 days before perigee (Perigee on May 15, 1948), the Moon's apparent diameter was near the average diameter.
The path width of the large annular solar eclipse of May 9, 1948, was about 200 meters and lasted only 0.3 seconds. A large annular eclipse covered over 99% of the Sun, creating a dramatic spectacle for observers in only an extremely narrow strip; however, it was fleeting, lasting just moments at the point of maximum eclipse.
During this eclipse, the apex of the moon's umbral cone was very close to the Earth's surface, and the magnitude was very large. The edges of the moon and the sun were very close to each other as seen from the Earth. Baily's beads on the lunar limb, which are usually only visible during a total solar eclipse, could also be seen. Therefore this eclipse was also an excellent opportunity to measure the size and shape of the Earth, as well as the mountains and valleys on the lunar limb. The National Geographic Society sent 7 teams respectively to Myeik in Burma, Bangkok in Siam, Wukang County (now belonging to Deqing County, Zhejiang) in China, Onyang-eup [ko]ofAsan-gun [ko] (now Onyang-dong, Asan City) in South Korea, Rebun Island in Japan, Adak Island in Alaska, as well as from the air onboard a Boeing B-29 Superfortress departing from Shemya Island. The scale of this observation was larger than ever before. In the end, the teams from the air and on Rebun Island got the best results with good weather conditions, while the results in Myeik and Bangkok were relatively good, Adak Island still somewhat valuable, Onyang-eup missing many goals, and Wukang with the worst results where there was rain during the eclipse. It was shortly after the end of World War II, and the observation in Japan showed friendship among the science community.[1] Kafuka [ja], one of the two villages on the island, supported the observation team, and a Solar Eclipse Observation Monument was built in 1954 to commemorate it.[2][3] The monument was first erected in Kitousu, the center of the observation site. It was moved to Itsukushima Shrine in 2003, across the sea facing Rishirifuji.[4]
Prior to it, the two hybrid solar eclipses of April 17, 1912 and April 28, 1930, also belonging to Solar Saros 137, also occurred with a magnitude close to 1. Observations were made near Paris, France and Camptonville, California respectively. There was an opportunity to make similar observations during the annular solar eclipse of May 20, 1966inGreece and Turkey, also belonging to the same solar Saros cycle.[2]
The Institute of Astronomy of the Academia Sinica (predecessor of Purple Mountain Observatory), Department of Physics of National Central University and Bureau of Surveying of the Ministry of National Defense also formed a team. The initial plan was to go to Guangdong, far from the observation site of the American team, hoping that the two teams would not be affected by bad weather at the same time. However after checking the weather, traffic and law and order conditions near Guangzhou, Hangzhou and Suzhou, the team finally decided on Cibiwu in Yuhang County. The decision was made based on the fact that meteorological data showed bad conditions generally across the whole Jiangnan in May, within the East Asian rainy season, and funding is limited so travel could not be made for a long distance. Besides, Xujiahui (Zi-Ka-Wei) Observatory estimated that there was 70% hope in Cibiwu, and it is close to the observation site of the American team, allowing the Chinese team to see the equipment of the American team for future reference.[5] Zhang Yuzhe, director of the Institute of Astronomy, visited the United States and Canada to study the spectrumofeclipsing binaries in 1946. However, the Ministry of Foreign Affairs of the Republic of China stopped funding him the return trip back to China. He took the opportunity of joining the observation team to return to China in March 1948,[6] and observed it together with Chen Zungui [zh].[7] In the end, due to the weather conditions, just like the American team which traveled to China, the Chinese team also only measured changes in the luminosity of the sun. The Qingdao Observatory, Sun Yat-sen University Observatory and the Department of Physics of Tongji University also made observations.[8]
This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[9]
The partial solar eclipses on January 3, 1946 and June 29, 1946 occur in the previous lunar year eclipse set.
| Solar eclipse series sets from 1946 to 1949 | ||||||
|---|---|---|---|---|---|---|
| Ascending node | Descending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 117 | May 30, 1946 Partial |
−1.0711 | 122 | November 23, 1946 Partial |
1.105 | |
| 127 | May 20, 1947 Total |
−0.3528 | 132 | November 12, 1947 Annular |
0.3743 | |
| 137 | May 9, 1948 Annular |
0.4133 | 142 | November 1, 1948 Total |
−0.3517 | |
| 147 | April 28, 1949 Partial |
1.2068 | 152 | October 21, 1949 Partial |
−1.027 | |
This eclipse is a part of Saros series 137, repeating every 18 years, 11 days, and containing 70 events. The series started with a partial solar eclipse on May 25, 1389. It contains total eclipses from August 20, 1533 through December 6, 1695; the first set of hybrid eclipses from December 17, 1713 through February 11, 1804; the first set of annular eclipses from February 21, 1822 through March 25, 1876; the second set of hybrid eclipses from April 6, 1894 through April 28, 1930; and the second set of annular eclipses from May 9, 1948 through April 13, 2507. The series ends at member 70 as a partial eclipse on June 28, 2633. Its eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of totality was produced by member 11 at 2 minutes, 55 seconds on September 10, 1569, and the longest duration of annularity will be produced by member 59 at 7 minutes, 5 seconds on February 28, 2435. All eclipses in this series occur at the Moon’s ascending node of orbit.[10]
| Series members 24–46 occur between 1801 and 2200: | ||
|---|---|---|
| 24 | 25 | 26 |
 February 11, 1804 |
 February 21, 1822 |
 March 4, 1840 |
| 27 | 28 | 29 |
 March 15, 1858 |
 March 25, 1876 |
 April 6, 1894 |
| 30 | 31 | 32 |
 April 17, 1912 |
 April 28, 1930 |
May 9, 1948 |
| 33 | 34 | 35 |
 May 20, 1966 |
 May 30, 1984 |
 June 10, 2002 |
| 36 | 37 | 38 |
 June 21, 2020 |
 July 2, 2038 |
 July 12, 2056 |
| 39 | 40 | 41 |
 July 24, 2074 |
 August 3, 2092 |
 August 15, 2110 |
| 42 | 43 | 44 |
 August 25, 2128 |
 September 6, 2146 |
 September 16, 2164 |
| 45 | 46 | |
 September 27, 2182 |
 October 9, 2200 | |
This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
| Inex series members between 1901 and 2100: | ||
|---|---|---|
 May 29, 1919 (Saros 136) |
May 9, 1948 (Saros 137) |
 April 18, 1977 (Saros 138) |
 March 29, 2006 (Saros 139) |
 March 9, 2035 (Saros 140) |
 February 17, 2064 (Saros 141) |
 January 27, 2093 (Saros 142) |
||
This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1901 and 2100 | |||
|---|---|---|---|
 September 9, 1904 (Saros 133) |
 August 10, 1915 (Saros 134) |
 July 9, 1926 (Saros 135) | |
 June 8, 1937 (Saros 136) |
May 9, 1948 (Saros 137) |
 April 8, 1959 (Saros 138) | |
 March 7, 1970 (Saros 139) |
 February 4, 1981 (Saros 140) |
 January 4, 1992 (Saros 141) | |
 December 4, 2002 (Saros 142) |
 November 3, 2013 (Saros 143) |
 October 2, 2024 (Saros 144) | |
 September 2, 2035 (Saros 145) |
 August 2, 2046 (Saros 146) |
 July 1, 2057 (Saros 147) | |
 May 31, 2068 (Saros 148) |
 May 1, 2079 (Saros 149) |
 March 31, 2090 (Saros 150) | |
The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's ascending node.
| 22 eclipse events between December 13, 1898 and July 20, 1982 | ||||
|---|---|---|---|---|
| December 13–14 | October 1–2 | July 20–21 | May 9 | February 24–25 |
| 111 | 113 | 115 | 117 | 119 |
 December 13, 1898 |
 July 21, 1906 |
 May 9, 1910 |
 February 25, 1914 | |
| 121 | 123 | 125 | 127 | 129 |
 December 14, 1917 |
 October 1, 1921 |
 July 20, 1925 |
 May 9, 1929 |
 February 24, 1933 |
| 131 | 133 | 135 | 137 | 139 |
 December 13, 1936 |
 October 1, 1940 |
 July 20, 1944 |
May 9, 1948 |
 February 25, 1952 |
| 141 | 143 | 145 | 147 | 149 |
 December 14, 1955 |
 October 2, 1959 |
 July 20, 1963 |
 May 9, 1967 |
 February 25, 1971 |
| 151 | 153 | 155 | ||
 December 13, 1974 |
 October 2, 1978 |
 July 20, 1982 | ||
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