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Message: <blockquote data-quote="Binastro" data-source="post: 3678447" data-attributes="member: 111403">Hi Lee,Strictly speaking at sea level the horizon distance is zero.A person with eyes 5ft 6 inches above sea level the horizon is 3 miles.At 60 miles the height needed to see the sea the other end is about 2,200 feet assuming no mirage effects.However, a person at 550 ft height above sea level would see a building say at 550 ft the other end.Sicily and Malta I think are quite hilly.I had two astronomers from Malta turn up about 1980.The had made a fine telescope from a 6 inch aperture objective from a periscope from a scrapped British submarine in Malta. I think there was a lot of this stuff lying around in the 1950s and 1960s.They paid all of £5, possibly a Ross objective?Unfortunately it broke and they wanted a replacement for near a fiver. I had nothing to offer them.6 inch aperture good long focus objectives were expensive in 1980.I gave them some quite good Plossls, so they wouldn't go away empty handed and maybe some other goodies.I found about 30 of these Plossls, which cost a total of flumpence. I have no idea what they were for.A local machinist made 30 brass mounts for them and they were good eyepieces, fairly short focus.There are quite a few good astronomers on Malta.The photo shown of Sicily from Malta at night clearely shows lights probably up to 70 miles distance along a very wide vista.</blockquote>