Archived posting to the Leica Users Group, 2000/11/06

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Subject: Re: [Leica] Leica lens turned into a telescope - can it be done?
From: Marc James Small <msmall@roanoke.infi.net>
Date: Mon, 06 Nov 2000 13:46:45 -0500
References: <3A05321C.13461.14BADD@localhost> <3A058139.742594F9@sympatico.ca>

At 10:04 AM 11/6/2000 -0000, clive sanbrook wrote:
>I used to have a Meade ETX astronomical telescope ((1000mm f19 (roughly) in
>photographic terms)) and even with an eyepiece which gave around 100 times
>magnification could only just see the rings on Saturn - And this was
>difficult to keep centred in the viewing area because of the earths
>rotation - IMO you would be stuggling to achieve this level of view with
>your propsed combination - I found that I was always disappointed in the
>amount and size of the detail that I could see.

There is something severely wrong with this.  First, the ETX would have
been an f/11, not f/19.  Second, the rings of Saturn were spotted by
Galileo with his original 4x25 monocular, though not clearly perceived as
rings.  A modern pair of binoculars of decent quality and aperture, such as
15x60's, can certainly reveal the rings.  

Astronomical viewing is most certainly a matter of training and experience.
 I have been viewing the heavens for more than four decades with small to
medium sized gear, and even my relatively poor eyes can see details some
eagle-eyed novice would miss.  

There ARE optical reasons why a camera lens does not normally make a decent
telescope, but a good telephoto can be so used with adequate results.

Marc

msmall@roanoke.infi.net  FAX:  +540/343-7315
Cha robh bas fir gun ghras fir!

In reply to: Message from "Roy Zartarian" <royzart@connix.com> (Re: [Leica] Leica lens turned into a telescope - can it be done?)
Message from Vick Ko <vick.ko@sympatico.ca> (Re: [Leica] Leica lens turned into a telescope - can it be done?)