Venus 2004
Navigation:
Document:
History of astronomical observation
It has been possible to observe the solar transits of Venus and Mercury since the 17th century due to the work of Johannes Kepler (1571-1630) and the publication of the Rudolphin Tables (1627).
Observations and Dates
7. 11. 1631 – The transit of Mercury was recorded by Pierre Gassendin (1592-1655) in Paris, Remus Ouietmus in Alsace, Father Cysatus in Tyrol, and an unknown Jesuit monk in Bavaria.
6.-7. 12. 1631 – The Venus transit took place at night and could not be seen in Europe. This transit was foreseen by Kepler, but he did not observe it.
4. 12. 1639 – Englishman Jeremiah Horrocks (1619-1641) observed the next Venus transit in Preston. This meant that the time between transits was not the 120 years predicted by Kepler. Horrocks guessed that the diameter of Venus is less than one circular minute, and the parallax thus created was 94 million kilometres. Details of his observations were published in 1662 and 1672. This transit was seen by William Crabtree of Manchester, though no official observation was recorded.
7. 11. 1677 – Edmund Halley (1656-1742) observed the Mercury transit from the island of St. Helena. He predicted the next events would be in 1761 and 1769. His records were published in the Philosophical Transactions of the Royal Society in 1691, 1694, and 1716.
Observation of 1761
French expeditions observed the transit of Venus from Vienna, Tobolsk in Siberia, and from the island of Rodriguez, north of Madagascar. The astronomers on these expeditions were César-François Cassini de Thury, Jean Chappe d'Auteroche, Alexandre Guy Pingre and Joseph-Jérôme Lefrançois de Lalande.
United Kingdom sent two groups with Nevil Maskelyne, Charles Mason, James Bradley, Jeremiah Dixon, John Wintrop. 120 professional astronomers observed this phenomenon at 62 locations around the world. The solar parallax was estimated at between 8.5" and 10.5".
Observation of 1769
French astronomer Chappe travelled with his group to the Baha, California peninsula, off the west coast of Mexico. Their observation was not complicated by weather, and ten days later, on June 18th, they observed a lunar eclipse. This event permitted them to determine the latitude. Unfortunately, all but two members of the group perished in a typhoid epidemic.
James Ferguson described transits of planets, and Thomas Hornsby published the meaning of these observations. Finally, England sent three expeditions to Wales and Dymond, Hell, and Borgrewing. James Cooke took a small third team to the South Sea, which was also sent to do some exploration. Astronomers such as C. Mayer of Germany, Mallet and Pictet of Switzerland, and Leonard Euler observed the Venus transit from various places in Russia.
151 professional astronomers observed this phenomenon at 77 locations around the world. The solar parallax was estimated at between 8.43" and 8.80".
Observation of 1874
The Venus transit was visible from China, Japan, North-eastern Asia and Australia. French astronomers devised a revolving photographic apparatus for this occasion.
Observation of 1882
Advances in the 19th century permitted more accurate results from observations. Astronomers from Belgium, Brazil, France, Germany and the U.S. participated.
The Belgian expedition used a heliometre, taking more than 700 photographs. The solar parallax was estimated at 8.911" (+/- 0.084)
The Americans used a horizontal telescope and photoheliograph, and estimated the parallax at 8.842 (+/- 0.0118).
France sent 10 expeditions with 35 scientists and estimated the parallax at 8,80".
The Brazilian expeditions observed the Venus transit from the Antilles, Brazil, and Punta Arenas in Chile.
German astronomers were in the US (Hartford), Argentina and Punta Arenas.
Sports Secondary Grammar School and Grammar School Kladno