For the Elan Valley Estate's IDA application, more than 200 individual light readings were taken at 13 sites over a 22 month period to demonstrate that the Estate would fit the criteria for this status. Analysis of the data revealed that the estate … "possessed exceptional starry skies and natural nocturnal habitat where light pollution is mitigated and natural darkness is valuable as an important educational, cultural, scenic, and natural resource".
This is one of the primary conditions for granting International Dark Sky Park status and so ideal for stargazing. With the Limiting Magnitude, (a measure of how faint a star is visible) varying from 6.3 – 6.8 across the Estate and an average reading of 6.5, the IDA accepted the decision to consider the whole of the Estate Lands as one single Dark Sky core unit, and not to break up the Park into small “core” sections as other applicants have done. For the 'up keep' of the IDA staus we will continue to record SQM readings on a regular basis.

Here is a map with the Elan Valley Estate SQM sites marked ...followed by the readings taken for the IDA Application...