Monday, June 22, 2009

The Royal Observatory...the beginnings

I almost forgot but today is the official beginning of The Royal Observatory in Greenwich, England as decreed by King Charles II.

"Greenwich Becomes Royal Pane on the Stars"


Randy Alfred

June 22nd, 2009


1675: Britain's King Charles II issues a royal warrant establishing an observatory at Greenwich. The Royal Observatory, then on the eastern outskirts of London, will enjoy a long and storied history and become a Prime piece of real estate.

Charles had a navy and a large merchant fleet. They needed better ways of navigating. Latitude could be determined by the angle of the sun in the sky at midday.

Longitude was a trickier matter. The hope was that accurate star charts, coupled with a table of the moon's position, would allow navigators to see how far east or west of Greenwich they had sailed.

So, the king decreed:

Whereas, in order to the finding out of the longitude of places for perfecting navigation and astronomy, we have resolved to build a small observatory within Our Park at Greenwich.

His Majesty also appointed John Flamsteed as the first Astronomer Royal. Architect-astronomer Christopher Wren designed the first building on the hill above the royal palace at Greenwich. Construction began Aug. 10 and was completed in 1676.

Edmund Halley — of comet fame — succeeded Flamsteed as Astronomer Royal in 1720. The lunar-distance method of charting longitude was proving none too reliable, and Parliament had established a 20,000-pound prize in 1714 for anyone who could find a better means.

If you had an accurate timepiece that told the time at Greenwich when you were on a ship hundreds, or even thousands, of miles away, you could figure out the longitude. Problem was, the accurate timepieces of the day were pendulum clocks, which aren’t accurate on a ship pitching and rolling at sea.

Clockmaker John Harrison eventually solved the problem and met the specs (half a degree of longitude or 2 minutes of time) with a series of highly accurate spring-driven clocks. But Nevil Maskelyne, the fifth Astronomer Royal, refused to believe that watchworks could compute longitude more accurately than the lunar-distance method. He kept insisting on more testing.

Harrison's four decades of work were finally recognized in 1773 by a begrudging parliamentary grant of 8,750 pounds (about $1.4 million in today's money). Several of his original timepieces are now on display at the Greenwich Observatory.

A century later, almost three-quarters of global commerce used nautical charts based on Greenwich, and an international conference in 1884 declared it the Prime Meridian of the world. The growing metropolis of London, however, soon enveloped Greenwich, and urban light and air pollution are not conducive to star-gazing.

The scientific institution known as the Royal Greenwich Observatory abandoned Greenwich in the mid-1950s, fleeing to Herstmonceux Castle in Sussex. RGO moved again in 1990, to Cambridge. The observatory buildings in Greenwich are now part of Britain's National Maritime Museum.

What's more, the Greenwich meridian is several hundred feet off zero degrees longitude on GPS systems. The Maritime Museum cites several reasons for this: variations around the globe necessitated by the Earth not being precisely spherical, the move to Herstmonceux, and inaccuracies in Doppler-satellite reckoning in the 1960s and 1970s.

But the grandly titled post of Astronomer Royal lives on. After 297 years, the position was separated from directorship of the observatory in 1972. The Astronomer Royal's post is now largely ceremonial, although the incumbent may be called on to give astronomical or scientific advice to the reigning king or queen.

"The Royal Observatory, Greenwich; a glance at its history and work" by E. Walter Maunder

John Flamsteed


Astronomers Royal

John Flamsteed (1675-1720)
Edmund Halley (1720-1742)
James Bradley (1742-62)
Nathaniel Bliss (1762-4)
Nevil Maskelyne (1765-1811)
John Pond (1811-35)
Sir George Biddel Airy (1835-81)
Sir William Henry Mahoney Christie ( 1881-1910)
Sir Frank Watson Dyson (1910-33)
Sir Harold Spencer Jones ( 1933-55)
Sir Richard van der Riet Wooley (1956-71)
Sir Martin Ryle (1972- 82)
Sir Francis Graham Smith (1982-90)
Professor Arnold W. Wolfendale (1990-1995)
Martin Rees, Baron Rees of Ludlow (1995-present)

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