Solar eclipse of August 18, 1868
Encyclopedia
A total solar eclipse
occurred on August 18, 1868.
, sketching the appearance of the corona, while Gustav Fritsch
accompanied an expedition to Aden
.
in Hyderabad State
, British India. It was the first total eclipse since Kirchoff's 1859 theory that the Fraunhofer lines in the solar spectrum correspond to the emission line of the different chemical elements present in the Sun. Correspondingly, Janssen observed the eclipse with the aid of a spectroscope. He noticed a bright yellow line (λ
= 587.49 nm) in the spectra of the solar prominence
s that could not be due to sodium as had previously been assumed, and was subsequently able to observe the same line even without the need for an eclipse. The same result was found independently by British astronomer Norman Lockyer, and both Janssen's and Lockyer's communications were presented to the French Academy of Sciences
on October 26, 1868.
, King of Siam, was able to calculate and predict the solar eclipse two years earlier. The calculation was correct on the place, the time and the type of the solar eclipse that would happen. According to the Thai Astronomical Society, the international astronomical community calls the eclipse "King of Siam's eclipse".
Solar eclipse
As seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...
occurred on August 18, 1868.
Observations
Captain Bullock observed from the Celebes seaCelebes Sea
The Celebes Sea of the western Pacific Ocean is bordered on the north by the Sulu Archipelago and Sulu Sea and Mindanao Island of the Philippines, on the east by the Sangihe Islands chain, on the south by Sulawesi, and on the west by Kalimantan in Indonesia...
, sketching the appearance of the corona, while Gustav Fritsch
Gustav Fritsch
Gustav Theodor Fritsch was a German anatomist, anthropologist, traveller and physiologist from Cottbus, best known for his work with neuropsychiatrist Eduard Hitzig on the electric localization of the motor areas of the brain...
accompanied an expedition to Aden
Aden
Aden is a seaport city in Yemen, located by the eastern approach to the Red Sea , some 170 kilometres east of Bab-el-Mandeb. Its population is approximately 800,000. Aden's ancient, natural harbour lies in the crater of an extinct volcano which now forms a peninsula, joined to the mainland by a...
.
Discovery of helium
French astronomer Pierre Janssen observed the eclipse from GunturGuntur
Guntur , is a city and a municipal corporation in the Indian state of Andhra Pradesh, located to the north and west of the Bay of Bengal. It is approximately to the south of the national capital, New Delhi and south east of state capital, Hyderabad. Guntur is the fourth largest city in Andhra...
in Hyderabad State
Hyderabad State
-After Indian independence :When India gained independence in 1947 and Pakistan came into existence in 1947, the British left the local rulers of the princely states the choice of whether to join one of the new dominions or to remain independent...
, British India. It was the first total eclipse since Kirchoff's 1859 theory that the Fraunhofer lines in the solar spectrum correspond to the emission line of the different chemical elements present in the Sun. Correspondingly, Janssen observed the eclipse with the aid of a spectroscope. He noticed a bright yellow line (λ
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
= 587.49 nm) in the spectra of the solar prominence
Solar prominence
A prominence is a large, bright feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona...
s that could not be due to sodium as had previously been assumed, and was subsequently able to observe the same line even without the need for an eclipse. The same result was found independently by British astronomer Norman Lockyer, and both Janssen's and Lockyer's communications were presented to the French Academy of Sciences
French Academy of Sciences
The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research...
on October 26, 1868.
Mongkut's calculation
MongkutMongkut
Phra Bat Somdet Phra Poramenthramaha Mongkut Phra Chom Klao Chao Yu Hua , or Rama IV, known in foreign countries as King Mongkut , was the fourth monarch of Siam under the House of Chakri, ruling from 1851-1868...
, King of Siam, was able to calculate and predict the solar eclipse two years earlier. The calculation was correct on the place, the time and the type of the solar eclipse that would happen. According to the Thai Astronomical Society, the international astronomical community calls the eclipse "King of Siam's eclipse".