On Tue, 17 Jun 2008 at 18:40:04, Jim Kewley
wrote in uk.sci.weather :

Excellent visibility dowm in SW Cornwall - Lundy easily visible from
the back of St Ives (around 100km?)

I tried plugging some numbers into this :

http://www.ringbell.co.uk/info/hdist.htm

... and you'd need to 800m up for the horizon to be at 100km - and I
know there's no land that high around St Ives.

Wouldn't it depend also on the height of land at the distant point?

Maybe - how high is Lundy?
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)