Re: ATM more on off-axis telescopes

["Andrew Schott" <aschott@cfl.rr.com>]

I was sitting here watching an old Twilight Zone on Sci-Fi and one of the
characters was played by Jack Elam.  I'll bet he'd have no problem using
this kind of scope.  Nor would Marty Feldman for that matter. ;-)

Happy New Year guys!  Thanks for all the consideration of my half baked half
mirror idea!

----- Original Message -----
From: "Steve Fejes" <jsfejes@swva.net>
To: <mayen1@mwt.net>; <ATM@shore.net>
Sent: Monday, December 31, 2001 10:33 AM
Subject: Re: ATM more on off-axis telescopes


>
> A 5" diameter spherical mirror will work OK when used off axis if the
> focal ratio is long enough.  F.15 might be long enough, but it won't
> give perfect star images at high power unless you use a correcting lens
> or mirror.
>
> Your idea of a pair of 5" off axis binoculars runs into a problem if you
> don't use a secondary mirror or prism though.  Your eyes would not be
> looking straight ahead, they would be trying to focus on images about
> 12" apart at the focal distance.  They would be looking near the center
> of each mirror, which would be spaced apart about 12" from center to
> center.  My head is about 7" wide, and the semi diameter of each mirror
> is 2.5".
>
> The heat from your body could be minimized if you extent the tube past
> your body.  So you would have your head between two tubes, and your
> body's heat would be largely deflected around the tubes.
>
> Steve
>
>