Re: ATM Need help with lengthening the tube on my Dob

["bill kocken" <wmkocken@hotmail.com>]

Thanks to those who sent suggestions.  I think I'm going to add a six sided
mirror box, made out of wood,  to the end of my tube.  I was able to figure
out how big to make the sides to fit snugly around the tube and the cuts
were pretty easy to make on my table saw.  I'll glue it up tonight and see
how it works.  I will stain and varnish the wood to match the finish on my
base, so I hope it will look OK.
Bill Kocken
----- Original Message -----
From: "Mike Spooner" <spooner@page.az.net>
To: "Bill Kocken" <wmkocken@hotmail.com>; <atm@shore.net>
Sent: Saturday, February 02, 2002 8:16 PM
Subject: Re: ATM Need help with lengthening the tube on my Dob


> This cell design may help get an inch or so without extending the tube.
>
> http://members.cox.net/rmscott/lh_scope/scope_rear_view.html
> http://members.cox.net/rmscott/lh_scope/primary_mirror_on_yoke.html
>
> --Mike
>
> ----- Original Message -----
> From: Bill Kocken <wmkocken@hotmail.com>
> To: <atm@shore.net>
> Sent: Saturday, February 02, 2002 5:46 PM
> Subject: ATM Need help with lengthening the tube on my Dob
>
>
> >
> >
> > Help,
> >   I made a newbie mistake.  I bought an Orion XT8 tube from a guy, and
> > ordered an 8" f6 mirror and other parts. Anyway, after putting it all
> > together, I find that the focus point is about 2" above my focuser, even
> > when it's racked all the way out out. I have several options, but only
one
> > good one (#3, I think)
> > 1.) Move the spider and focuser further out to the end, but I don't want
> to
> > cut new holes, and I really don't have 3" of room anyway.
> > 2.) Add height to the focuser, but 3" is way too much.
> > 3.) Move the main mirror back.  In order to do this, I need to lengthen
> the
> > tube.
> > Does anyone have a good idea on how to best move my main mirror back
about
> > 3".  The tube I'm using is balck sheet metal.
> >
> > Thanks,
> > I really enjoy reading helpful hints and discussions in this forum.
> > Bill Kocken
> >
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>
>
>