Where longitude is the distance east or west of the Prime Meridian line, latitude is measured by the distance north or south of the equator. What is the latitude of the Royal Observatory? The cross-hairs in the eyepiece of the Transit Circle precisely defined Longitude 0° for the world.įind out more about Airy's Transit CircleĪs the Earth’s crust is moving very slightly all the time the exact position of the Prime Meridian is now moving very slightly too, but the original reference for the prime meridian of the world remains the Airy Transit Circle in the Royal Observatory, even if the exact location of the line may move to either side of Airy’s meridian. The transit circle was built by the 7th Astronomer Royal, Sir George Biddell Airy, in 1850. In 1884 the Prime Meridian was defined by the position of the large 'Transit Circle' telescope in the Observatory’s Meridian Observatory. Greenwich was chosen as the centre for world time.įind out more about Greenwich Mean Time Where is the Prime Meridian? When the railway and communications networks expanded in the 1850s and 1860s, there needed to be an international time standard. There were no national or international conventions which set how time should be measured, or when the day would begin and end, or what length an hour might be.
Since the late 19th century, the Prime Meridian at Greenwich has served as the reference line for Greenwich Mean Time, or GMT.īefore this, almost every town in the world kept its own local time.
The line itself divided the eastern and western hemispheres of the Earth - just as the Equator divides the northern and southern hemispheres. If you stand with one foot on one side and the other on the left, you are perfectly in the middle of east and west, according to the prime meridian line. Every place on Earth was measured in terms of its distance east or west from this line. The line in Greenwich represents the historic Prime Meridian of the World - Longitude 0º. The decision was based on the argument that by naming Greenwich as Longitude 0º, it would be advantageous to the largest number of people. Therefore the Prime Meridian at Greenwich became the centre of world time. The second was that in the late 19th century, 72% of the world's commerce depended on sea-charts which used Greenwich as the Prime Meridian. The first was the fact that the USA had already chosen Greenwich as the basis for its own national time zone system. There were two main reasons for the choice. Why does the Prime Meridian run through Greenwich? By comparing thousands of observations taken from the same meridian it's possible to build up an accurate map of the sky. Information on this website does not guarantee that the developer / project is registered under the Real Estate (Regulation and Development) Act, 2016 or is compliant with the same, and the same should also be verified independently.A meridian is a north-south line, selected as the zero reference line for astronomical observations. Users of this website are hereby advised to exercise due diligence and to independently validate and verify all information about any property / project before deciding to purchase the same or taking any other action. Nothing contained herein shall be deemed to constitute any sort of legal advise, solicitation, marketing, offer of sale, invitation to offer, invitation to acquire etc. Information regarding real estate projects (including the property / project detail, listings, floor area, location, price etc.) are either third party content or sourced from public sources. The details displayed on our website are for information purposes only. We do not in any way facilitate and cannot be deemed to be facilitating any transaction between seller / developer and the visitors / users of our website. only acts as a medium for advertisement / information content.