Re: [ATM] Mersenne (was : Looking for information on a telescopedesign)

["Francis J. O'Reilly" <foreilly@verizon.net>]

Richard,

This year at Stellefane there were numerous accessible telescopes. Mostly 
using the Springfield design but with twists. I think there were about five 
telescopes with various different interpretations of the design on display.

Best regards,

FJO
----- Original Message ----- 
From: "Richard" <cnc@cncservo.co.uk>
To: "Scott Milligan" <atm@atmlist.net>
Sent: Thursday, August 30, 2007 11:11 AM
Subject: Re: [ATM] Mersenne (was : Looking for information on a 
telescopedesign)


> Hi Scott,
>
> For me, it's more than a matter of comfort, it's a necessity. I spend
> all of my time out of doors in a wheelchair. I've been studying low
> level eyepiece designs to quite some degree. The Mersenne was top of
> my list. It seemed the ideal solution - turn the beam into a much
> smaller afocal beam, do whatever you want with it, and view it in
> comfort with a decent small instrument. Then I ray traced it and
> discovered exactly the problem that Vlad is talking about. I admit it
> is influenced by where you put the system stop, but for me it was as a
> complete show stopper.
>
> No, I haven't looked *through* one, but I don't see how that has the
> slightest relevance. The importance to me is that I've looked very
> carefully *at* it, and it has a big draw back. If you can
> minimise the distance from the secondary to the viewing instrument you
> can minimise that drawback, but then you may as well use a simple
> diagonal mirror and focuser.
>
> -- 
>
> Best regards,
>  Richard in the UK
>
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> 


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