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Message: <blockquote data-quote="Binastro" data-source="post: 3207825" data-attributes="member: 111403">. Hi Gijs,Thanks for your extensive reply.I rather quickly write this, so excuse any errors.The first telescope made in England in 1576-Action optics.If you look up Action optics, you will find a piece on telescopes.Also Dr Allan Chapman has discussed this in lectures and also in papers in journals.A telescope is a device that makes far objects look nearer, so anything that does this is to me a telescope.I think that it is a mistake to think that Europeans in the 1300s and earlier had a monopoly of wisdom. They didn't.The paper about the Ceylon lenses makes it clear that these opticians were more advanced than the Europeans.Because of the question of copyright I don't want to quote more from the paper on the Ceylon lenses until and if I get permission from the copyright holder.I will just quote one more sentence from the paper in the interests of research. ' The civilisation and culture of Ceylon was far in advance of ours of the same period' (that is 1340).There is also the question of the extensive availability of printed texts.In the context of lenses or telescopes made in the 1300s and earlier I think that it is unlikely that much will be found in print.By the time of the Dutch in the early 1600s printing was well established and freely available.I think that is is unlikely that the lens maker in Ceylon in 1340 would not have known that using two lenses, one weak and one strong makes a telescope. He had the necessary stone tools to make these different focal length lenses and just because Europeans were struggling to make good lenses it does not mean that he was unable to make good lenses from high-quality amethyst.With these crafts, the skills were passed down from generation to generation and probably not written down.Last night, I tried simple lenses, which are admittedly of reasonably good quality. I used a low-power watchmakers plastic magnifier of perhaps three times magnification. A 60 mm common magnifier with a small insert. I think this magnifies two times and four times. And also some spectacle lenses. These lenses ranged in focal length for about 50 mm to 400 mm.I was really very surprised how good the image was just handholding each lens without any tube whatsoever. This was in normal room light and I was looking at an alarm clock about 3.5 m away. The resulting inverted telescopes of two times, three times, and four times were either good, very good and in one case excellent. With these handheld open telescopes I could see detail on the alarm clock which was totally invisible to me just wearing my spectacles.If I find any more information or references I will add this later.</blockquote>

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