This article is part of FT Globetrotter’s Guide to London
The navigator has solid links to time and distance. The Earth rotates 360 degrees on its axis every 24 hours. This means that a person standing at the equator moves eastwards by about 111km, once every four minutes. For a long time, people have recognized that the passage of the sun, stars and other bodies across the sky caused by rotations with careful observation and some neat calculations is a reliable way to organize and determine the position of the Earth’s surface.
Encouraged by my father-in-law, who was an Air Force navigator, I learned how to navigate in 1999 as part of my long-stage dream of training for a private pilot license. Since then, I have been fascinated by the diverse mix of mental histories of geography, astronomy, mechanics, mathematics and navigation.
Today, Greenwich, the Royal Observatory in southeast London, is a fantastic museum, and for almost 300 years the site has been the centre of astronomical and navigable observation and research. Its handsome buildings, some of which are registered in I and II, one designed by Sir Christopher Wren, sits on the hills of Greenwich Park, directing beautiful, unclosed views of Greenwich, the Thames, Canary Wharf, and 9km-meters of central London. It owes its very existence to the urgent 17th century needs for navigational research. King Charles II was founded in 1675 with a simple way to find practical ways to fix longitude for precise navigation, as maritime powers became important for the success of its people. The walks outlined below provide insight into the history of navigation and timekeeping and their pivotal role within it.
Meridian Observatory
A good place to start is Meridian Astronomy, a collection of rooms built between the 17th and 19th centuries. It features large windows and an open roof to observe the sky along the meridian.
Some of the beautiful instruments on display are aligned as they were originally with meridians with the names of the astronomer royals who established them: Flamsteed (1689), Halley (1725), Bradley (1750), Airy (1851). They used telescopes to plot the position of the sky bodies in the same way that the town is plotted on a map of the surface of the Earth. The telescope, set up in the mural quadrant, consisting of telescopes mounted on a metal quarter circle that names the device, and the Bradley meridian, is a fun example of 18th-century scientific instruments, but the most impressive one is the 1851 Airy Transit Circle.
The telescope’s observations were accurately observed by a microscope on the transport support block, and were even timing with a reliable clock. Before the International Meridian Conference of 1884, there was no agreed World Prime Meridian-Zero Longitude reference line, with many countries and organizations using various meridians for purposes. The meeting resolved that the meridian running airy transport should now become the main meridian of the Earth. With the meridian in Greenwich, GMT simultaneously became a global reference to time. However, in 1988, the International Earth Rotation Service (IERS) meridian was launched, based on a new set of coordinates calculated from satellite data. The difference in the way satellites are corrected and the location of the transit circle means that the IERS meridian is actually 102.5 meters east of Airy, but it is still based on his main meridian. By placing a smartphone with a mapping app on the Prime Meridian, you can demonstrate this and impress your friends.
Flamsteed House
Next, cross the observation deck – as all visitors do, stand on the Prime Meridian stepping into the Eastern and Western Hemispheres, entering the museum’s oldest building, Flamsteed House. It’s a very practical design. On the first floor is the former royal residence of astronomers who lived for nearly 300 years until 1948. The room was presented to George Airy to inform the children of nautical sciences to advise the city of Chester at the height of the river and teach the voyage of the river.
Above the residential area is an octagonal room, and you rarely see the original interior designed by Christopher Wren. With large windows designed to provide an unobstructed view of the sky, the unintentionally local area created sublime, bright space and tall ceilings, allowing for the long pendulum fitting required for the accuracy of the room’s clock. It’s beautiful, but the room is defective. As a measure of cost savings, it was built on the foundations of the previous building. In other words, it is not consistent with the meridian and does not irritate the observation.
Back on the first floor, another gallery explains the role of observatory stations in longitude issues and finds reliable and practical ways to identify east-west locations of the ocean to allow for safe and efficient maritime travel. Two rival theories competed to solve it. One involves observing celestial bodies and relying on accurate maintenance of time in the ocean. Both had their supporters, advantages and disadvantages.
Personally, my highlight of this gallery, and in fact, the museum, is the watch of one of my heroes, John Harrison (1693–1776). Harrison is a skilled and highly determined watchmaker, and has worked for years to resolve longitude with an incredible watch that pursues the fortunes offered by the British Government’s longitude awards. The four mechanisms on display are as original as they are beautiful, making up for all the bad things that a dangerous 18th century sea voyage casts.
Another floor down is Time and Greenwich Gallery. The exhibition shows the modern timekeeping and the role the observation deck played in creating increasingly accurate clocks. The pursuit of accuracy is important here, and the attractive watch shows how the regular swing of a Pendurum watch has been replaced by electronic and other devices. One clock signal was sent by Telegraph to provide GMT to British railways, creating standard times across the nation, replacing the 19th century system of chaos, in which all towns set clocks at the noon sun. Another clock on display was a source from 1924 to 1949, a time signal used by the BBC as the basis for its hourly “6 pip” broadcast.
Further accuracy was provided based on the incredible clock based on the frequency of the components of the atoms (1949) and the subsequent GPS signals (1993) from satellites in the universe (1993). Quantum clocks under development will eventually measure accuracy over billions of years.
Time & Society Gallery and the Great Equatorial Telescope
Returning across the courtyard above the children’s observatory is a gallery of time and society. Civilization is carried out with accurate timekeeping and here records the inventions that have achieved it. A device that utilizes the exquisite sundial, astrolabel, and quadrants. Mechanical clocks with complex escapes and pendulums; and modern electronic and GPS timekeeper. Whether it’s a London traffic time recorder, it reminds me that the WWII “zigzag” clock used to change ships The WWII “zigzag” clock is used to change courses to avoid enemy attacks, or that it reminds me of a Russian clock for timing movements in chess matches.
Raising the spiral staircase will allow you to lead you to the great equatorial telescope of 1893, housed in the Onion Dome, which will become the unique landmark of the Greenwich skyline. It is the largest refractive telescope in the UK and is still used in museums for public astronomy sessions. In the first viewing, it appears to be aligned at an inexplicably strange angle, but this alignment means that the telescope moves parallel to the equator, and that it can be easily tracked across the sky as it slowly progresses through the stars. The telescope’s attachment to a frame originally designed for narrow instruments adds its quirky look. However, the appearance was deceptive, and the precise observation of the telescope helped to calculate the mass of double stars rotating with each other.
When time runs out, don’t forget to check the watch with a 1852 Shepherd Gate clock when you leave. The first public clock showing the average time in Greenwich (though there is a 24-hour face) is still very accurate and is a last reminder of the importance of Greenwich to help us know our time and place.
Have you visited Greenwich, the Royal Observatory in London? Please let me know in the comments below. Follow FT Globetrotter on Instagram at @ftglobetrotter
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