Tupman 1874 Honolulu Hawaii Transit of Venus

The 1874 Transit of Venus Expedition to Hawaii was an astronomical expedition by British scientists to observe the December 8 transit of Venus at three separate observing sites in the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

, then known as the Sandwich Islands. It was one of five 1874 transit expeditions organized by George Biddell Airy, Astronomer Royal at the

Royal Observatory, Greenwich The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in ...

. The purpose of the expedition was to obtain an accurate estimate of the astronomical unit (AU), the distance from the Earth to the Sun, by measuring

solar parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

. Previous efforts to obtain a precise value of an AU in 1769 had been hampered by the

black drop effect The black drop effect is an optical phenomenon visible during a transit of Venus and, to a lesser extent, a transit of Mercury. Description Just after astronomical transit#Contacts, second contact, and again just before astronomical transit#Con ...

. There is a collection of papers relating to this expedition at the Cambridge Digital Library.

Background

George Biddell Airy began preparations for the expedition in 1869 and procured funds in June of that year. Airy spent 1870–71 acquiring the necessary supplies and equipment. He made George Lyon Tupman, a captain in the Royal Marine Artillery, the lead astronomer of the Sandwich Islands expedition (known as Station B) in April 1872 and Tupman was also given responsibility for overseeing the organisation of all five official British expeditions and training the 22 observers. Tupman's journals recording the pre-expedition work at Greenwich have been digitised.

Team

The Sandwich Islands team was composed of seven observers - Professor George Forbes, Henry Glanville Barnacle, John Walter Nichol, Lieutenant Francis Edward Ramsden, Lieutenant E. J. W. Noble, Captain George Lyon Tupman, and Richard Johnson - plus three Sappers of the Royal Engineers. In June 1874, the team left Liverpool in two groups carrying 93 tons of provisions on . They stopped along the way and met up in Valparaíso, Chile; they reached Honolulu Harbor on 9 September. The voyage out, and the rest of the expedition, were depicted in a series of caricature drawings by Lieutenant Noble, which have been digitised. The team manned observing stations on three different islands. The primary observing station was established by George Lyon Tupman on the island of Oahu in the Apua district of Honolulu. The site was atop the bell tower of Kawaiaha`o Church. Nearby Ali`iolani Hale, at that time the Hawaiian Kingdom's capitol building, was a second Oahu location atop the building's clock tower manned by an American observer. Two auxiliary stations were established, one in Waimea,

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...

, manned by Richard Johnson with assistance from Lieutenant R.H. Wellings of HMS ''Scout'', and another in

Kailua Kailua () is a census-designated place (CDP) in Honolulu County, Hawaii, United States. It lies in the North Koolaupoko, Hawaii, Koolaupoko District of the island of Oahu, Oahu on the windward and leeward, windward coast at Kailua Bay. It is i ...

, Hawaii, manned by George Forbes and Henry Glanville Barnacle."Science & Technology - The Key to Hawaii's Economic Future" State of Hawaii Department of Business, Economic Development & Tourism October 1998. As well as observing the transit on 8 December 1874, the observers undertook a large amount of work to establish the positions, particularly the longitudes, of the three observing sites. This information was fed into the Trigonometrical Survey of the Kingdom of Hawaii, then in progress and led by Professor

William DeWitt Alexander William DeWitt Alexander (April 2, 1833 – February 21, 1913) was an educator, author and linguist in the Kingdom of Hawaii and Republic of Hawaii. He then constructed maps for the Territory of Hawaii. Early life Alexander was born in Honolulu ...

. Tupman's journal of the Honolulu Station and Forbes's journal of the Kailua (Hawaii) Station have been digitised. Charles Darwin's son,

Leonard Darwin Leonard Darwin (15 January 1850 – 26 March 1943) was an English politician, economist and eugenics, eugenicist. He was a son of the naturalist Charles Darwin, and also a mentor to Ronald Fisher, a statistician and evolutionary biologist. B ...

, was a photographer on the 1874 Transit of Venus Expedition to New Zealand, after which he traveled to Hawaii aboard the ''Mikado'' to meet the team in Honolulu.

Publications

George Biddell Airy published an ''Account of Observations of the Transit of Venus'' in Hawaii in 1881, with more than 200 pages about the expedition. Airy, George Biddell, ed. 1881.
Account of Observations of the Transit of Venus, 1874, December 8, Made under the Authority of the British Government: And of the Reduction of the Observations
'' N.p.: Printed for Her Majesty's Stationery Office.

Background

Team

Publications

References

Further reading