J2974 : Spider, Black Mountain North Triangulation Pillar

near to Legoneil and Springfield, Ireland

Spider, Black Mountain North Triangulation Pillar
Spider, Black Mountain North Triangulation Pillar
Detail of the 'spider' on Black Mountain North Triangulation Pillar J2974 : Black Mountain North Triangulation Pillar. Considerable damage to the concrete and the screw cap is not marked (most other OSNI examples have either "TRIANGULATION STATION
ORDNANCE SURVEY" or "OSNI TRIANGULATION STATION").
OSNI Triangulation Stations
The re-triangulation of Northern Ireland by the Ordnance Survey Northern Ireland began in 1950. This was the first complete survey of Northern Ireland which included observations with the new primary triangulation of the country, its connection with the Republic of Ireland and the cross-channel connection between Ireland and Great Britain. This began by OSNI establishing a series of triangulation stations throughout the country. Almost all of these stations were topped by trig pillars and 80, mainly primary and secondary pillars, had been constructed by October 1949. Measurements between primary stations began in 1950 and measurements for these and the secondary stations were completed by July 1956. The construction and measurements for tertiary stations were completed later (probably no later than the mid 1960s). Only two stations are not topped by pillars - Lighthouse Island, marked by a brass rivet, and Ardglass, which utilised the top of a high stone folly. The older triangulation stations on the Lough Foyle Base Line were also re-surveyed as part of this process. A majority of the stations are still extant today but a few have been removed or destroyed.
Creative Commons Licence [Some Rights Reserved]   © Copyright Rossographer and licensed for reuse under this Creative Commons Licence.
year taken
2012
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J2974, 12 images   (more nearby)
Photographer
  (find more nearby)
Image classification?
Supplemental image
Date Taken
Monday, 2 January, 2012   (more nearby)
Submitted
Tuesday, 3 January, 2012
Geographical Context
Uplands 
Place (from Tags)
Divis Mountain  Belfast  Black Mountain 
Subject Location
Irish: geotagged! J 293 748 [100m precision]
WGS84: 54:36.3184N 5:59.9311W
Photographer Location
Irish: geotagged! J 293 748
View Direction
Northeast (about 45 degrees)
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