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Subject: Re: [M]: LX200/f6.3 FOCAL REDUCER/NGF-S FOCUSER
From: Anvilblue
Reply To: mapug@shore.net
Date: Sun Dec 21 00:25:23 1997

In a message dated 97-12-18 14:19:09 EST, you write:

<< John W Downs wrote:

> Yes, the focus reducer is designed to butt up next to the prime focus
> with no other devices first, this will insure a f/6.3 ratio.
>
> downs
> Willard Observatory
> (foothills of Mt. Palomar)
>
> On Wed, 17 Dec 1997 13:28:49 -0500 Jim Wilson <jcwilson@usaor.net>
> writes:
> >My question to the group. If I am going to use The f6.3
> >focal reducer with a NGF-S focuser what order of attachment
> >does one use? Does it matter what goes on first?
> >
> >Thanks
> >Jim
> >
> >

O dear, I suppose I will get in trouble now. However, here goes.

The focal reduction you get depends only upon the focal length of the
focal reducer and the distance between the focal reducer and the final
image plane. This is an optical fact.
No amount of discussion will change the optical equations.

Doc G


Hi,

I guess< well not really > why this is called a Reducer/Correcter . Get the
whole correcter end of the Reducer part? Designed to Correct the Coma yah see
when the scope is being used for photography. Ergo, the correction " Should "
be at the proper distance from the primary mirror. OR they would just call it
a reduction lens. I would love to show and xerox for all of you the why other
reduction lenses will not yield a "full frame" 35 mm neg that is corrected
edge to edge. It's why I use the device at the rear of the telescope before I
attach anything else. GET IT ?

Bye Bye