QUOTE (tty @ Feb 24 2006, 09:34 PM)
I doubt these medieval or older telescopes for several reasons.
First telescopes have such obvious military and naval applications that it seems highly unlikely that they would ever have been "forgotten". Once they were invented they spread very quickly.
The same thing is true about spectacles which were invented early in the fourteenth century (at least that is what contemporary sources say) and also spread quite rapidly.
Second there are quite a number of optical works from the Middle Ages and early modern times, none of which describes a telescope in unequivocal terms.
I know it seems strange that it took 300 years to progress from spectacles to a refractor, but there are any number of inventions that could have been made centuries or millenia earlier from a technological point of view if only somebody had had a bright idea. Take the hot-air balloon or the windmill or the stirrup for example.
tty
To add to the example quoted by ljk4-1, there are also incredibly modern looking aircraft models found in antic egyptian tombs. Toys, again...
Military? The militaries are as dumb as the others and as much subject to social conformism and fear of what is new. What distinguishes the ancient from us, I think, is that they had an incredibly strong pigheadnesness idea about what should be or not, especially about customs, morals, etc (which did not forbad them to break moral rules at least as often as us, anyway, as having an opinion is a thing, to embody it is another). More subtly, they were lacking some concepts which seem obvious for us today. When we see an unknown new apparatus, we think "it is science" and we immediatelly look what we can do with it. The ancient, I guess, were rather thinking "it is magic, it is a trick, it is not in the order of things, so it is bad, I should not use it, its appeal is a trick of the devil" (don't we were thinking in this way still recently? I remember when I was a child, elder people were reluctant about new inventions...). So, imagine that a glass worker found inadvertently how to make a magnifying glass. He build several, and finds how to make a telescope. If he is not simply afraid of it, he will speak of this to only little people, otherwise he knows he will be procecuted, whipped and killed for blasphemy. At best, he will have some disciples, and write some words about what he saw (milky way made of many stars). Even if by chance, a general finds the telescope, and uses it for battle, he will use it for himself, and keep is secret, by fear of being accused, or by interest simply.
So this difference of mind can explain that science did not appeared in the Antiquity, where however many conditions were set for it to appear.
The difference is that we have EVOLVED and that society features and concerns such as science, human rights, social care, democracy, appeared "spontaneously" when this evolution allowed it.
When an overal society evolution allows it, features arise and spread, in much the same way as in a nuclear reactor. But if the conditions are not yet present, any discovery or insight is bound to degenerate and disappear, as in an under-critical reactor where a reaction follows a decreasing chain. If it is really under-critical, a fission can produce one or two other fissions, but no more.