In the past, GMT has been a term with two different meanings. The more specific and conventional meaning is to use midnight as the zero hour of each and count upwards from there. These are listed below:. This time zone with a zero offset from UTC is observed by Greenland.
This time zone has no offset from UTC and is observed by several European countries during the winter. The WEST time zone is used in the summer.
In Africa, Morocco and the Western Sahara use this zone. This military zone has a zero offset from UTC and is used for military purposes in aviation. The time difference between these two concepts is minimal, but the differences still remain. Instead, countries that participate in the practice move to a new time zone temporarily during the time period. In its early history, the United Kingdom evolved into a maritime nation, which is any nation that borders the sea and is dependent on it for a majority of the following activities:.
This evolution resulted in British mariners using chronometers set to GMT which they could use to find their longitude from the Greenwich meridian which is the basis for zero degrees longitude. These chronometers were portable time standards that allowed the mariners to utilize celestial navigation to find their longitude and therefore their location.
The Isle of Man adopted the standard in , Jersey followed in , and Guernsey in This was followed by Ireland in Amadora Lisbon. Ipswich England. Saint-Louis Saint-Louis. Wigan England. Bo Southern Province. Croydon England. Kaolack Kaolack. Walsall England. Mansfield England. Oxford England. Korhogo Savanes. Warrington England. Slough England. Bournemouth England. Peterborough England. Ziguinchor Ziguinchor. Cambridge England. Doncaster England. Tema Greater Accra.
York England. La Laguna Canary Islands. Poole England. Gloucester England. Burnley England. Huddersfield England. Telford England. Dundee Scotland. El Jadid Casablanca-Settat. Blackburn England. Basildon England. Sikasso Sikasso.
Teshi Old Town Greater Accra. The most obvious thing about the Shepherd gate clock is that it has 24 hours instead of the usual 12 hours. From to , the Shepherd master clock led the time system of Great Britain. Using the telegraph wires, the clock sent the time to the major cities such as London, Edinburgh, Glasgow, Dublin, Belfast, and more. Even more, from time was also sent to Harvard University in Cambridge and Massachusetts. Back then, the Shepherd gate clock played the most important role in distributing accurate time to people in various places of the world.
The first thing you notice about the clock is that it has 24 hours on its face rather than the usual That means at 12 noon the hour hand is pointing straight down rather than straight up. Initially, the Shepherd gate clock showed astronomical time according to which the counting of the 24 hours of a day starts at noon.
However, in the 20th century. The clock was changed to GMT and from this time the counting of 24 hours started from midnight. Some of these are seriously mind-blowing:. Toggle navigation. Ready to get your time right? Until the midth century, almost every town kept its own local time, defined by the Sun.
There were no national or international conventions which set how time should be measured. This meant there was no standard timings for when the day would begin and end, or what length an hour might be. However, the s and s saw the expansion of the railway and communications networks. This meant the need for an national time standard became imperative.
British railway companies started introducing a single standard time across their networks, designed to make their timetables less confusing. It was mostly Greenwich Mean Time that they used. It officially became 'Railway Time'. There were two main reasons for this.
The first was that the USA had already chosen Greenwich as the basis for its own national time zone system. As the reference for GMT, the Prime Meridian at Greenwich therefore became the centre of world time and the basis for the global system of time zones.
Therefore this also became the start of the Universal Day. The meridian line is marked by the cross-hairs in the Airy Transit Circle eyepiece. Find out more about the Airy Transit Circle. The Shepherd gate clock can be seen at the gates to the Royal Observatory. It was the first clock ever to show Greenwich Mean Time directly to the public.
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