From the physics lab in Manchester where the atom was first split, to the hut in Gloucestershire where Edward Jenner developed the first vaccine, England’s historic places are a hotbed of innovation.
Louise Devoy, Curator of the Royal Observatory in Greenwich, tells us about the stratospheric impact of this place.
Today we rely on our mobile phones to tell us where we are and what time it is, but it’s easy to forget the complex scientific and technological principles that underpin these numbers.
As Britain’s first state-funded scientific institution, the Royal Observatory played a vital role in both timekeeping and navigation for nearly 3 centuries. It’s an essential and irreplaceable part of our history with a variety of interesting characters and innovative technology, all set within a beautiful English park near the River Thames in Greenwich.
It all started with a rumour that began to circulate around the English court during late 1674 when sources claimed that French astronomers had improved a means of navigating by the Moon and stars.
With new trade routes opening up towards Asia, Africa and the Americas, European governments were keen to improve navigation at sea that could save lives and enhance profits on increasingly lucrative commodities such as coffee, tea, spices, textiles and timber.
As a consequence of these rumours, King Charles II was persuaded to set up an observatory and the first Astronomer Royal, John Flamsteed (1646–1719), started work in Christopher Wren’s elegantly-designed new observatory in 1676.
For the next 40 years, Flamsteed diligently observed the stars, plotting their position according to the time at which they crossed a meridian (north-south) line.
He also devised Greenwich Mean Time (GMT). Flamsteed realised that the sun did not cross the meridian line at exactly the same time each day when compared against the steady beat of a pendulum clock.
To compensate for this, he created an average (mean) time that evened out the difference between solar time and clock time, as measured by an observer at Greenwich.
Sadly, Flamsteed died before his work was published, but the quest to improve navigation at sea continued to occupy successive generations of Astronomers Royal.
In particular, the fifth Astronomer Royal, Nevil Maskelyne (1732–1811), created the annual publication of astronomical data known as the ‘Nautical Almanac’, an essential guide for every navigator at sea that continues to be published today by the UK Hydrographic Office.
Maskelyne and his assistants carefully observed and measured the stars each clear night, sending out parcels of data to a network of mathematicians across the country who number-crunched the observations into a useable format.
Meanwhile, the Longitude Act of 1714 inspired a range of scholars and inventors to try and devise a means of determining longitude (your east-west position) at sea, enticed by the chance to win a reward of £20,000 (equivalent to several million pounds today).
After many designs and trials, the carpenter and clockmaker John Harrison eventually received the reward by the early 1770s for his innovative marine timekeeper, known as H4.
By comparing their local time (measured by the sun) to the time back home (maintained by the marine timekeeper), mariners could convert their time difference into a measure of longitude. Given that the Earth rotates once on its axis (360°) each day (24 hours), 1 hour’s time difference is equivalent to a longitude difference of 15 degrees (360°/24). This was simple in theory, but highly difficult to measure in practice.
Over the next few decades, craftsmen adapted Harrison’s design to create the marine chronometer which became an essential piece of kit for every navigator.
By taking note of the dropping of the Observatory’s roof-top time ball at 1pm each day, navigators on the River Thames could check their chronometers before heading out to sea.
In addition, chronometers issued to Royal Navy ships were sent to the Royal Observatory between voyages to be tested and reassessed.
Meanwhile, the rapid expansion of the railway network across Britain during the 1840s meant that Observatory time was important for more than just navigators at sea.
For centuries, people had relied on sundials and clocks set to local time to help structure their day. This was impossible to use for long distance rail journeys when the time difference between cities could vary by 30 minutes or more.
The railway companies all agreed to coordinate and use Greenwich Mean Time, relying on a series of electric signals distributed from the Observatory via the telegraph network.
Finally, in October 1884, delegates at an international conference in Washington DC decided to recommend that all governments should adopt the meridian defined by the Observatory’s Airy Transit Circle instrument as the prime meridian (zero degrees longitude), from which all locations on Earth could be defined.
Discussions at this conference also sparked the creation of the international system of time zones which we continue to use today.
So, after our whirlwind tour across 3 centuries of hard work and innovation, we can clearly see that the Royal Observatory is not just an irreplaceable part of British history but an essential part of our interconnected global history that we still rely on today.
Find out more about visiting Royal Museums Greenwich, including the Royal Observatory here.
Further reading
0 comments on “Saving Lives with Clocks and Telescopes”