thumb|left|Astronomers in Turkey observing the 1936 eclipse
A total solar eclipse occurred at the Moon's descending node of orbit on Friday, June 19, 1936,[1] with a magnitude of 1.0329. 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 3.3 days after perigee (on June 15, 1936, at 22:10 UTC), the Moon's apparent diameter was larger.[2]
The path of totality crossed Greece, Turkey, USSR, China and the Japanese island of Hokkaido. The maximum eclipse was near Bratsk and lasted about 2.5 minutes. A partial eclipse was visible for parts of Europe, Northeast Africa, Asia, and northern North America.
The Evening Standard reported that the "preparations for to-day's eclipse have been going forward for the past two years", and that a British expedition led by amateur astronomer R. L. Waterfield saw "excellent atmospheric conditions" from its observation point on Cap Sunium. Similar observations were made by teams in Hokkaido, some hours later, allowing their observations of the Sun's corona to be compared "to find out whether any changes in shape or in detail of the corona have taken place in this interval". A Russian team in Krasnoyarsk reported successful observation from a high-altitude balloon, where scientists "hoped to make observations at a height of some 15 miles". There were also observers in the south of Greece, from Greece, Italy and Poland, the latter of which were "successful in obtaining cinematograph pictures of the eclipse". Several long prominences (more than a million miles long) were observed, as well as the planet Venus.
A United States expedition in Siberia conducted experiments on the ionosphere, with the Associated Press reporting that "indications that the earth's electrified roof, which, many miles above the surface of the globe, reflects back radio impulses, is formed mostly as a result of ultra-violet sun radiations appeared in preliminary results of the solar eclipse observations".
Except for the total solar eclipse of June 29, 1927, which was only visible from the sparsely populated Arctic Ocean coast, this was the first total solar eclipse visible within the Soviet Union since its founding (the previous one was in 1914 when it was still ruled by Russian Empire). 28 Soviet teams (including 17 astronomical observation teams and 11 geophysical observation teams) and 12 international teams from France, the United Kingdom, the United States, Italy, Czechoslovakia, Sweden, the Netherlands, China, Japan and Poland made observations in the Soviet Union.[3] There were 370 astronomers in the teams. To offer better conditions for the 70 foreigners among them, the Central Committee of All-Union Communist Party (Bolsheviks) promoted a policy to reduce railway and water transportation fair by 50%.[4] The Academy of Sciences of the Soviet Union established a special committee and made preparations for two years. The government raised 60,000, 365,000 and 400,000 roubles respectively in 1934, 1935 and 1936. Experts from the Leningrad Astronomical Institute manufactured 6 coronagraphs with a diameter of 100 mm and a focal length of 5 metres, distributed to Pulkovo Observatory, Sternberg Astronomical Institute, Moscow branch of the, Institute of Astronomy of Kharkiv National University, V. P. Engel'gardt Astronomical Observatory and . Besides observations on the ground, balloons[5] and aircraft[6] were also used.
Among them, Pulkovo Observatory and its Simeiz branch (now Crimean Astrophysical Observatory) sent three teams. The first studied the chromosphere and solar prominences in Akbulak, Orenburg Oblast, led by Boris Gerasimovich, chairman of the Special Committee for Solar Eclipse Observation of the Academy of Sciences. The second went to Sara, Orenburg Oblast, led by Gavriil Adrianovich Tikhov. The third studied the corona in Omsk, led by . The team of the Sternberg Astronomical Institute went to the village of Bochkarev (Бочкарёв) in the suburbs of Kuybyshevka (now Belogorsk, Amur Oblast) to study the spectrum of the chromosphere and corona, the polarization of the corona and the light bending in gravitational fields proposed by the theory of relativity. The team of Kharkiv Observatory studied the luminosity, polarization and chromospheric spectrum of the corona in Belorechensk, Krasnodar Krai, led by Nikolai Barabashov. The team of the Georgian National Astrophysical Observatory studied coronal radiation. The team of the Moscow branch of the All-Union Astronomical and Geodetic Society made standard coronagraph observations and led amateur observations nationwide. The team of V. P. Engel'gardt Astronomical Observatory studied the visible spectrum of the corona with diffraction gratings and took images of the corona with standard coronagraphs in Kostanay Region in today's Kazakhstan.[7] [8]
An American team of 24 people led by Donald Howard Menzel went to Akbulak together with the Pulkovo Observatory team. A team of four astronomers of Arcetri Observatory, Italy led by Giorgio Abetti went to Sara together with another team of the Pulkovo Observatory.[9]
Japan sent 20 astronomy observation teams and 18 geophysics observation teams to Hokkaido. In addition, teams from the United Kingdom, the United States, India, China, Czechoslovakia and Poland also went to Hokkaido. Some were successful and some were not. Interestingly, another total solar eclipse of August 9, 1896 was also visible in the coastal town Eshashi of Esashi District, which received many foreign scientists at that time. Therefore, despite the inconvenient transportation, Kwasan Observatory of Kyoto University and a Chinese team still selected it as the observation site.[10]
In November 1934, astronomer organized the Chinese Solar Eclipse Observation Committee shortly after the establishment of the Purple Mountain Observatory, to prepare for observations of this eclipse in 1936, and the solar eclipse of September 21, 1941 (another total solar eclipse in 1943 was also visible in Northeast China, the Soviet Union and Japan, but there was no plans or actual activities of any kind of observations in China). The committee was inside the Institute of Astronomy, with Cai Yuanpei being the chairman, and Gao Lu the secretary-general. It asked for a fund of 30,000 from the government during the preparation, and received another 120,000 from the British, French and American portions of the Boxer Indemnities Committee. Although the path of totality of this eclipse passed through northeast China, it was relatively remote located on the Sino-Soviet border, and was already under control of Manchukuo, a Japanese puppet state. In the end, 2 teams were sent abroad. This was the first time that Chinese scientific observation teams made observations abroad.
One team consisted of only Zhang Yuzhe and, going to Siberia, the Soviet Union. They initially planned to go to Orenburg Oblast with better weather conditions, but because the time was limited, they finally chose Khabarovsk. The two took a ship from Shanghai to Japan on May 31, then transferred to a train to Tsuruga and then transferred again a ship, arriving in Vladivostok on June 9. After staying there for 2 days, they took an international train and arrived in Khabarovsk on June 11. The goals include taking images of the corona, measuring the time of the eclipse, and comparing the darkness of the sky during totality with that of twilight. On the eclipse day, although it was clear in the morning and noon, the eclipse was clouded out in the afternoon, and it rained heavily in the evening. The observation was not successful.
Another team consisted of 6 people, with being the leader, and, Zou Yixin, Wei Xueren, and, going to Hokkaido, Japan. The team departed from Nanjing on June 3, arrived in Tokyo on the night of June 8, went to Hokkaido the next day, and arrived at the town of Esashi at noon on June 11. The town also received many foreign scientists during another total solar eclipse on August 9, 1896. The goals included taking images of the corona, taking films for public screening and gaining experience for observing the other total solar eclipse in 1941. There were clouds at first on eclipse day, but the sun came out of the clouds before the second contact. 3 ordinary corona images, 1 ultraviolet image and 3 sets of movies were taken.
In Nanjing, only a partial eclipse was visible. Although not worth observing compared with a total eclipse, Kao Ping-tse and Li Mingzhong who stayed in Nanjing still recorded the time of the solar eclipse, to check the accuracy of previous calculations.[10] [11]
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.[12]
| First Penumbral External Contact | 1936 June 19 at 02:45:25.3 UTC | |
| First Umbral External Contact | 1936 June 19 at 03:49:28.3 UTC | |
| First Central Line | 1936 June 19 at 03:50:07.0 UTC | |
| First Umbral Internal Contact | 1936 June 19 at 03:50:45.8 UTC | |
| Ecliptic Conjunction | 1936 June 19 at 05:14:49.8 UTC | |
| Equatorial Conjunction | 1936 June 19 at 05:15:50.0 UTC | |
| Greatest Duration | 1936 June 19 at 05:17:59.5 UTC | |
| Greatest Eclipse | 1936 June 19 at 05:20:31.1 UTC | |
| Last Umbral Internal Contact | 1936 June 19 at 06:50:22.6 UTC | |
| Last Central Line | 1936 June 19 at 06:50:58.9 UTC | |
| Last Umbral External Contact | 1936 June 19 at 06:51:35.0 UTC | |
| Last Penumbral External Contact | 1936 June 19 at 07:55:44.4 UTC |
| Eclipse Magnitude | 1.03291 | |
| Eclipse Obscuration | 1.06691 | |
| Gamma | 0.53889 | |
| Sun Right Ascension | 05h50m06.8s | |
| Sun Declination | +23°25'41.1" | |
| Sun Semi-Diameter | 15'44.3" | |
| Sun Equatorial Horizontal Parallax | 08.7" | |
| Moon Right Ascension | 05h50m17.9s | |
| Moon Declination | +23°57'12.9" | |
| Moon Semi-Diameter | 16'02.1" | |
| Moon Equatorial Horizontal Parallax | 0°58'50.8" | |
| ΔT | 23.8 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.