Longitude in Stamps

The Royal Observatory is one of London’s most recognisable landmarks, and was designed by one of Britain’s greatest architects Sir Christopher Wren. The 10 August marks 340 years since the building’s foundation stone was laid. The Royal Observatory is now part of The Maritime Museum and as the home of The Prime Meridian it is the centre of world time.

European Architectural Heritage Year, Royal Observatory, Greenwich Stamp (1975)

European Architectural Heritage Year, Royal Observatory, Greenwich 8p Stamp (1975)

The building was commissioned by King Charles II to produce a reliable map of the sky in order to improve navigation at sea . Navigating a ship by the stars can be seen in the 37p Astronomy stamp from 1990.

Astronomy, Stonehenge, Gyroscope and Navigation by Stars 39p Stamp (1990)

Astronomy, Stonehenge, Gyroscope and Navigation by Stars 39p Stamp (1990)

Distance could also be measured in Longitude by using the time of two separate locations. Sailors calculated local time by the position of the sun, but to know the time back at home they needed to take a clock aboard the ship, the conditions of which caused the clocks to become inaccurate. In 1714 the Government passed an Act of Parliament offering £20,000 to whoever could solve the ‘Longitude Problem’ and produce a way of keeping time at sea.

Astronomy, Greenwich Old Observatory and Early Astronomical Equipment, 31p Stamp (1990)

Astronomy, Greenwich Old Observatory and Early Astronomical Equipment, 31p Stamp (1990)

The competition was won by John Harrison, a joiner from Yorkshire, whose expertise in clock making allowed him to produce a devise that could withstand the conditions and motions of a journey.The image on the right of the above stamp shows the first sea fairing clock ‘H1’, a chronometer that compensated for the movement of the ship with two swinging balances.

Marine Timekeepers 24p Stamp (1993)

Marine Timekeepers 24p Stamp (1993)

Marine Timekeepers 28p Stamp (1993)

Marine Timekeepers 28p Stamp (1993)

Marine Timekeepers 33p Stamp (1993)

Marine Timekeepers 33p Stamp (1993)

Marine Timekeepers 39p Stamp (1993)

Marine Timekeepers 39p Stamp (1993)

Harrison produced numerous attempts to construct a clock that would provide longitude within half a degree. His final and successful clock the ‘H4’ was produced by watch maker John Jeffery to his specification and resembled a pocket watch. The stamp issue Maritime Timekeepers from 1993 celebrated his final product. Captain Cook in fact took a copy of Harrison’s ‘H4’ with him on his second voyage and it proved instrumental when navigating the journey.

Millennium Series, The Travellers' Tale, Captain Cook and Maori 63p Stamp (1999)

Millennium Series, The Travellers’ Tale, Captain Cook and Maori 63p Stamp (1999)

Greenwich is also home to Greenwich Mean Time and the Prime Meridian. A meridian is a north south line very much like the equator which acts as Longitude 0°, where astronomical observations are measured from.  The 31p stamp below depicts Sir George Airey’s Transit Telescope which is the precise point longitude is measured from.

Centenary of Greenwich Mean Time, Sir George Airey's Transit Telescope 31p Stamp (1984)

Centenary of Greenwich Mean Time, Sir George Airey’s Transit Telescope 31p Stamp (1984)

Centenary of Greenwich Mean Time, Greenwich Observatory 28p Stamp (1984)

Centenary of Greenwich Mean Time, Greenwich Observatory 28p Stamp (1984)

The Greenwich Meridian was chosen as the Prime Meridian for the world by an International Conference represented by 25 nations. At this time most sea charts were measured using the Greenwich Meridian, so it seemed logical to continue. The line passes through the observatory and is identified by the steel line on the ground and a green laser that shines across London.

Greenwich Prime Meridian Laser Across London

Greenwich Prime Meridian Laser Across London

As an island nation, sea travel has always been important in Britain. This is reflected in these beautiful stamp designs which celebrate not just sea travel but the innovations and achievements of those that made it possible. This theme of innovation and human endeavour is one that has always been important in the history of the postal service, as well as Britain as a whole, and as such will be prominent in the galleries of The Postal Museum when it opens in late 2016.

– Georgina Tomlinson, Philatelic Assistant

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