Part 8: Greenwich and Royal Observatory

20150506

The Trip

The Photos

The photos below are what we saw.

The clipper Cutty Sark is docked at Greenwich.  Built in 1869 it represented the pinnacle of British sailing technology and held the record for fastest ship afloat for ten years.  After the Suez Canal opened, steam power took over and the Sark came to dominate the sailing route to Australia.  Given more time, we would have loved to tour the ship.

The walking route to the observatory passed the Maritime Museum and this nice statue.  We were pressed for time, so we did not stop to investigate.

This ship in the bottle is a scale model of Nelson's command ship.  The odd sail fabric is "artistic license".

We saw a few of these food trucks in the London area.  I think the French made the truck in the 1950s and now they serve as rolling kitchens.

I was surprised by the continual jet noise but it turns out that Greenwich is on the flight path for Heathrow.

The hill that houses the observatory provides a commanding view of the Canary Wharf area of metropolitan London.

Greenwich is all about telling time and location.  To know your location, you must know your local time.  Time is referenced to the sun, but knowing time is key to calculating a ship's location.  Failure to have a good fix on ship's location results in wrecks.  After a number of tragic wrecks with large losses of life and money, the British Admiralty sought to solve the problem once and for all.  The Royal Observatory was part of that solution plan.

Standardizing distance measures is critical for both location certainty and repeatability in the construction processes for ships.

Exact solar noon was measured at the observatory and communicated to the outside world by dropping this red ball exactly at noon.  The sailors down in the flats on the River Thames would synchronize their ship's clocks to the dropping of the ball before heading out to sea.

The spike on this monument points at the center of the earth's rotation.  The Prime Meridian, the zero point for measurement of longitude, runs along the steel line in the patio and through the center of the spike.

Knowing when local noon occurs is useful, but to make that measurement something more than a curiosity, you must be able to interpolate time between successive noons.  So, an accurate clock is needed.  Greenwich had many fine examples of old attempts at building a precision measurement tool for time.

Each of these two clocks were used by staff at the observatory to measure the movements of the stars in an attempt to provide a better way to locate a ship's position on the high seas.

The large grandfather-style clocks kept reasonable time on shore.  But on the open seas, the rolling of the ship destroyed the accuracy of the timing.  The Admiralty commissioned a contest to build an accurate timepiece that could handle shipboard travel.  The first attempt was John Harrison's H-1 clock.  The H-1 used counter-oscillating masses to make it more resistant to ship's motion.  And, the H-1 was independent of the direction of gravity.  Over the years, Harrison's clocks got better and better, but still eluding the huge reward for the challenge.  In essence, the Admiralty attempted to stiff him and Harrison petitioned the King to get payment -- which he got.  His efforts were an important factor in Britain establishing naval superiority and holding it for so many years.  See the Royal Observatory's page on this fascinating story.

Many other clock designs were built and tested, but none so transformatory as the Harrison line.

This is a clock tower mechanism used to move the hands on large clocks.

Our time in the museum was up and they ran us out.  To return to London, we had to take the Docklands Light Rail under the Thames.  The drill bit used to bore the tunnel was on display at the station.

Pre-fabricated sections of concrete were installed to make the final tunnel lining.  The lining can be seen in the photo above.

On the north side of the Thames, we could see some newer structures including this cool bridge.

The Docklands and the Canary Wharf used to host a huge amount of shipping.  These dock cranes were left over from that era and are now monuments.

After a significant trip, we ended up back at Blackfriar's station and back on the street.  It was rush hour and the ubiquitous double-decker buses were out in force.

Photos and Text Copyright Bill Caid 2015 all rights reserved.
For your enjoyment only, not for commercial use.