Focuser extension into tube
PFAFF2@delphi.com
Tue, 07 Mar 1995 23:12:39 -0500 (EST)
> Return-path: <owner-atm@best.com>
> Received: from shell1.best.com by delphi.com (PMDF V4.3-9 #7804)
> id <01HNVAQ68WGW9EFODS@delphi.com>; Tue, 07 Mar 1995 21:29:32 -0500 (EST)
> Received: (majordom@localhost) by shell1.best.com (8.6.10/8.6.5)
> id QAA19595 for atm-outgoing; Tue, 7 Mar 1995 16:57:29 -0800
> Date: Tue, 07 Mar 1995 19:57:37 +0001 (EST)
> From: Mitch Berkson <mitchb@world.std.com>
> Subject: Focuser extension into tube
> In-reply-to: <m0rm8j6-0005CkC@roger.pixar.com>
> Sender: owner-atm@best.com
> To: atm@best.com
> Reply-to: atm@best.com
> Message-id: <Pine.3.89.9503071934.A8530-0100000@world.std.com>
> MIME-version: 1.0
> Content-type: TEXT/PLAIN; charset=US-ASCII
> Content-transfer-encoding: 7BIT
> Precedence: bulk
>
> I am thinking of building a focuser and am looking at the JMI 2" NGF as a
> guide. The specs I have show that it extends 1.4" into the tube.
> Doesn't that put it in the light path (assuming the tube is 2" bigger
> than the mirror)? Thanks.
>
> Mitch
>
>
It would extend a little more then 0.4" into the light path because
the cone of light is greater in diameter then the mirror at the focuser.
If your telescope has a 1 degree field you would add this to the mirror
dia. to find the unvignetted diameter.
Bob Pfaff