Yesterday evening, thanks to clear weather conditions, the island of Sicily and the eruption of Mt Etna was visible from the island of Malta (almost 200km away)!

http://www.timesofmalta.com/articles/view/20131128/local/etna-eruption-visible-from-m alta.496661

Wow!

I knew that sometimes Sicily is visible but I never even imagined that the spewing lava would be visible!

The post has stimulated me to discover how far away one might be able to see a mountain 3350m high if one were at Sea level. You may all know this already - but if not........

The pictures of course show a fair bit of Mt Etna below its summit. Based purely on curvature of the earth and with no issues of air quality pure trigonometry determines that someone at sea level could see the top 350 metres of a mountain 3350 m high 195kms away. If one is above sea level in Gozo I guess one adds the height one is at to that of Mt Etna - but even being up 100 metres doesn't add a lot See http://www.ringbell.co.uk/info/hdist.htm

BUT
of course other factors come into play. Particularly that of refraction which can extend this distance a variable amount depending on the exact weather conditions and the temperature gradient they create in the atmosphere. It appears that just after dusk and "over sea" conditions are best. See http://mintaka.sdsu.edu/GF/explain/atmos_refr/horizon.html

interesting!