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Re: [ATM] catoptric telescope (Mircea Pteancu)
This is very interesting. Reflecting eyepieces are known to be
possible, but I've not yet seen one in the historical
literature. There are some good reasons why they aren't used, though
I'm not certain about the details - probably a big obstruction or a
tilted element's astigmatism. But there have been some hints over
the centuries that telescope designers considered all catoptric
telescopes: for example, James Gregory, when he first described the
Gregorian in 1663, classified it as a catadioptric (lens + mirror),
and mentioned catoptric, or entirely reflecting telescopes - but no
details. I don't know of any description of an all-reflecting visual
telescope in modern papers.
So, please send Csillag a congratulations, and please let us know
when details can be posted.
--Peter Abrahams
>Date: Sat, 9 Feb 2008 12:27:47 -0800 (PST)
>From: Mircea Pteancu <mirceapte@yahoo.com>
>Subject: [ATM] catoptric telescope
>To: atm@atmlist.net
>Message-ID: <234412.79287.qm@web35801.mail.mud.yahoo.com>
>Content-Type: text/plain; charset=iso-8859-1
>
>While I was doing a visit to my friend Attila Csillag (so all the
>ATM community of the city of Arad,Romania, was in one room) ,he
>proudly introduced to me his catoptric telescope.This TCT is of his
>invention and is using only mirrors.Parameters are :primary dia.
>72mm F/10 and eyepiece is still a concave aluminized mirror of 30mm
>dia. f=80mm.The power of the telescope is about 10x.Outside it was
>bad wheather so no chance to test the telescope on stars.But I was
>admiring pits in the walls and the dirt on the windows of the garage
>across the road with this telescope.No need to insist on the
>achromatism of the image.There are many other things to comment on,
>like :why spherical mirrors, restricted field of view,why no sliding
>eyepiece-mirror and so on...Anyway it is the first and only visual
>telescope I ever saw without any lenses.A picture of the telescope
>can be seen at:
>
>http://www.atmlist.net/contrib/mirceapte-at-yahoo-dot-com/poze%20Laura%20153-copy.jpg
>
> Also ,after greatfully reading the kind replies,I done some
> material searching and I will come back with a few more questions
> on my thread ''pinched mirror''.Regards,Mircea
Peter Abrahams telscope@europa.com abrahams.peter@gmail.com
The history of the telescope and the binocular:
http://home.europa.com/~telscope/binotele.htm
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