Wednesday, March 26, 2014


With BST (British Summer Time) approaching, I thought I'd send this snap of the view from my grandson's bedroom window, taken last week....the old Royal Observatory, Greenwich - Flamsteed House.
The green laser light is the Prime Meridian.
Flamsteed House is displays some of John Harrison's chronometers...and the Greenwich Planetarium is next door. Nearby is the National Maritime Museum - the old home of the Brigg Raft.


Ken Harrison said...

One should just be able to make out the orange Greenwich Time Ball atop Fla,steed House. From 1833, ach day, at 12.55, the time ball rises half way up its mast. At 12.58 it rises all the way to the top. At 13.00 exactly, the ball falls, and so provides a signal to anyone who happens to be looking. again.

The Time Ball drops at 13.00 GMT during the winter months and 13.00 BST during the summer. (excluding windy weather)

Before creating Stardard Time, different parts of the county had various times - from half to a full hour variation.

From about the C17th (obviously b4 radio and the Internet)some folks use to take the time from Greenwich...and then travel about London selling-on the time for a fee to business and retail folk about the those days, accurate time, was a commodity that could be sold!!

Ken Harrison said...

...although GMT time is still universally used, we have now moved to an advanced scientific age....since 1972, Universal Time (UT) - electronic/astronomical calculated time - is used in scientific industries - ie satellites, GPS, mobile phones & etc.

Those folks who have spent time in the forces will re-call that GMT time is called 'Zulu', while the local time is called 'Local'.
For example, Zulu time (GMT) was often used in signals (telegrams), so various overseas bases could adjust Zulu to Local 'AIRCRAFT LEFT BRIZE NORTON 20:30 ZULU STOP (STOP = full stop) ETA SHARJAH 02:45 ZULU STOP'
As Sharjah was GMT+4 hours, the a/c's ETA was 06:45 hrs Local time.