Many years ago, I spent three years in a cupboard at the University of Bristol - trying to figure out how fuzzy electron diffraction patterns were, and if that fuzziness told us anything useful. I guess it did, a bit (PhD awarded).
Little did I know that my expert knowledge of image fuzziness might one day come in useful again.
Based on observations from the office window - this is my scale for the fuzziness (or lack of fuzziness) of the view across Quendale Bay and (sometimes at least) to Fair Isle. And yes, it is entirely subjective.
10/10 As clear as possible - Fair Isle appears to be in 3D - and just a short swim away (apparently)
9/10 I can see the Fair Isle North Lighthouse
8/10 Looks very clear - and maybe the Fair Isle radio mast can be seen
7/10 Clear outline - not as clear as 8 but way better than 6
6/10 Fair Isle outline clear - but it's only 2D
5/10 Fair Isle only just visible (if you know it's there)
4/10 No sign of Fair Isle - Lady's Holm clear (and beyond)
3/10 Features clear on Lady's Holm - but looks distinctly fuzzy beyond.
2/10 Lady's Holm just visible
1/10 I can see the sea (just)
0/10 I can't see the sea
And in case you weren't aware how variable the weather can be on Shetland - all the images were taken in May 2021.
There is, of course, an entirely separate nocturnal visibility scale too (it's simpler)
A. I can see the Sumburgh Head light and the Fair Isle North light from my sofa (a two-lighthouse-evening).
B. I can see the Sumburgh Head light.
C. Have they turned the lighthouse off this evening?