Centenary of Greenwich as the Prime Meridian

In the year 1884 Delegates from 25 Countries met in Washington DC and decides The Greenwich Observatory should be the Prime Meridian.  Since that time, all the Nations used Greenwich Meridian as Zero Longitude and at the same convention, Greenwich Mean Time (GMT) was put into effect for Navigational use at the Sea, in the Air..... and in the Exploration of the Solar System.

In the Year 1984 Great Britain issued of 4 stamps to celebrate the Centenary of adoption of Greenwich as Prime Meridian.

In my collection i have 4 First Day Covers & 4 Maxim Cards of 1984 depicting the history of  Greenwich Observatory right from its beginning.

Now the Greenwich Observatory was turned into a museum (National Maritime Museum, Greenwich).

Along with 4 First Day Covers & 4 Maxim Cards of the Year 1984 which is Centenary Year of Greenwich as the Prime Meridian i am also herewith enclosing one letter which i received from National Maritime Museum in the Year 1994. I wrote a letter to Greenwich Observatory about GMT then i received reply from the Museum.