|Greenwich Park (adjacent Royal Observatory)|
|Distance (N) from Greenwich|
|OS map details||OS Explorer: 161 or 162|
|OS grid ref||TQ 38882.77346|
|WGS84 lat/long||51.478031, -0.001507|
|Type||Ground (line) | Wall (line) | Sign on post(s)|
|Marking date||c. 1908|
|Access||Restricted (park opening hours)|
William Christie, the Astronomer Royal at the time of this marking did not share his predecessor George Airy’s thoroughness for documentation. Although no written record of the mark’s arrival has been found in the Observatory’s archive at Cambridge or in any publications connected with the Observatory, its presence in Christie’s time is recorded in a message on a postcard written by an American tourist that carries a postmark of 25 November 1908: ‘Saw the line which marks the prime meridian, crossed it, and stood with one foot in the east the other in west longitude’. Photographic evidence suggests the Line was unlikely to have been marked much before this date. The marking seems to have occurred at about the same time as another undocumented event – the repainting/re-enamelling of the dial of the 24-hour gate clock, which is located nearby, alongside the gates of the Observatory. Until well into the second-half of the twentieth century, it was the clock rather than the Line that most visitors came to see.
The original stonework was carved with the words Greenwich Meridian along with a grove to indicate the Meridian’s position. The stone appears to have been rather soft, for the words are worn in the c.1915 photo and no longer visible in the one dated c.1925. When the sign carrying the words Greenwich Meridian was set into the Observatory railings above, is not known, but it was clearly in place by the mid 1920’s.
The line was re-cut at the instigation of Harold Spencer Jones within two years of his appointment as successor to Dyson. The work was done by the Ministry of Works at some point between 22 May 1934 & 30 April 1935. At the same time, a descriptive plate was mounted alongside.
In preparation for the formal opening of the Octagon Room at the Observatory by HRH the Duke of Edinburgh on 8 May 1953, the Ministry of Works replaced the stone ‘meridian line’, in the path outside the Observatory, with the present bronze strip inset into larger stones in order to make the line more prominent. The stone slip on the retaining wall of the Observatory was added at the same time.