Posts Tagged ‘lunar tables’

THE THIRD MAN – CHARLES GREEN

Tuesday, August 15th, 2017

‘The grim roll-call broke his [Cook’s) heart…the death of the astronomer Charles Green marked a wave of those who ‘departed this life’….By the end of January [1771] they had barely enough men to man the ship [HMS Endeavour]’. Vanesssa Collingridge, Captain Cook, The Life, Death and Legacy of History’s Greatest Explorer, Ebury Press, 2002

Swinton: Charles Green son of ‘a prosperous’ free-hold Yorkshire farmer, born in Swinton towards the end of 1734, received a broad education with a strong emphasis on science.

London: John his elder brother took Holy Orders and established a school in Soho, London where Charles found his ‘heavenly passion’ astronomy. He stayed and taught mathematics after graduating.

Greenwich: In 1760 Charles Green applied successfully for the position of Assistant Astronomer at Greenwich Observatory. He went on to serve as Chief Assistant to three (3) Astronomer Royals, James Bradley, Nathaniel Bliss and briefly Reverend Nevil Maskelyne.

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In 1675 King Charles II engaged Sir Christopher Wren to design a National Observatory. Wren considered the ruins of Greenwich Castle a perfect site. For although Oliver Cromwell’s Roundhead Model Army had destroyed its buildings during The Protectorate Interregnum (1653-59) its foundations were intact.

Greenwich: In 1676, Rev. John Flamsteed, England’s inaugural Astronomer Royal, took up residence in the newly minted Greenwich Observatory. He remained in the role until his death in 1720.

Edmond Halley of comet fame succeeded Flamsteed holding  the post for twenty-two (22) years until his death in 1742.

Rev. James Bradley followed Halley. His tenure too was lengthy 1742-1762. Bradley is celebrated principally for his work on the speed of light. In 1728 he estimated light moved at the speed of 295,000 km (183,000 miles) per second.

Three (3) centuries later Bradley’s calculations were amended slightly to 299,790 km (186,290 miles) per second. Had Bradley stuck to light and left longitude to Mr. John Harrison inventor of the H-4 sea-going ‘pocket-watch’ many a sea-farer would not have met a watery end. Bradley died in 1762

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MALICIOUS MASKELYNE

Monday, August 14th, 2017

‘The Transit [of Venus] was more than just an astronomical curio, it was the key to a wealth of information about the universe, information that would be seized upon by the intensely curious men of science who characterised the age’. Vanessa Collingridge, Captain Cook, The Life, Death and Legacy of History’s Greatest Explorer, Random House, 2003

England – 1663: In 1663 during the reign of King Charles II (1660-1685) a collection of ‘intensely curious men of science’ – the ‘Invisible College’ – morphed into the Royal Society.

A century later, the Society flowered under the patronage of King George III (1720-1820), to become one of the world’s most celebrated scientific institutions.

In 1767 with the Transit of Venus in the offing – 3 June 1769 – its second appearance that decade – the Society petitioned King George III for financial support to send observers to report on the phenomenon.

‘That the passage of the Planet Venus over the Disc of the Sun, which will happen on the 3rd of June in the year 1769, is a Phaenomenon (sic) that must, if the same be accurately observed in proper places, contribute greatly to the improvement of Astronomy on which Navigation so much depends.

 As the [Fellows] are in no condition to defray this Expense about £4,000 pounds, exclusive of the Expense of the Ships…with all humility and submit the same to your Majesty’s Royal consideration’. Cited, H.C. Cameron, Sir Joseph Banks, Angus and Robertson, Sydney, 1968

1768 – February: To that end James Douglas 14th Earl of Morton, then President of the Royal Society, on 15 February 1768 penned a Memorial requesting the Monarch’s financial support.

Royal money was forthcoming for it was clear accurate and reliable ‘Navigation on which so much depends’ equated with domination over the world’s oceans. Domination would expedite expansion of territory and trade and with strategically placed ‘bases’ more likely would assure victory in time of conflict.

‘And the sum of £4,000 pounds clear of fees, [was] to be placed at the disposal of the Society…On March 5th of the next year, 1768, the Navy Board was instructed by the Admiralty to purchase a suitable vessel for the great voyage to the South Seas’. Cameron, Sir Joseph Banks, Angus and Robertson, 1968

Deptford -1768, 5 March: Admiralty settled on the Earl of Pembroke. Renamed Endeavour she was a typical coal carriercat-built bark’ of 368 tons ‘stoutly built, flatly bottomed of shallow draught’.

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LOTTO AND LONGITUDE

Wednesday, August 9th, 2017

‘But by reason of the motion of the Ship, the Variation of Heat and Cold, Wet and Dry, and the Difference of Gravity in different Latitudes, such a watch hath not yet been made”. And not likely to be, either, he implied’.  Isaac Newton cited, Dava Sobel, Longitude, Fourth Estate, London, 1998

‘Not likely’ however in 1736-7 on a timed voyage, England to Lisbon aboard HMS Centurian, H-1 an early model of John Harrison’s  marine watch – had proved a reliable time-keeper.

‘He [Harrison] succeeded, against all odds, in using the fourth – temporal – dimension to link points on the three-dimensional globe’. Sobel. ibid.

Accurate time-keeping was essential for the calculation of longitude at sea. John Harrison a Yorkshire carpenter solved that problem with ‘pocket watch’. His invention gave a ship’s precise position when beyond sight of land.

‘John Harrison, the man who solved longitude in 1759’. Peter Ackroyd, Revolution, Macmillan, London, 2016

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