Re: ATM Air Spaced lens

[Colin Caissie <optic@gwi.net>]

I think I read in ATM 2 or 3 that if you want to build a refractor, you
ought to have a lathe.  I don't know if you can cleverly fab a refractor
cell as easily as a Reflector.  It's got to hold the lenses almost tight,
needs close diameter clearances, and be adjustable.  

I would bet a custom built cell would cost, especially in the 6-9" range.  

Wouldn't it be possible to buy a slice of RMT  (Round mechanical tubing)
from Marmon-Keystone or some other tubing vendor that is the correct
diameter, cut/file to length and add retainer clips, a Round rubber o-ring
(make one up from an o-ring kit or buy the round rubber from McMaster-Carr)
and Mount this on a disk with the clear aperture cut out. Hat shape.  Mate
this with push-pull screws to another plate which mounts to the tube.  It
looks do-able with some basic tools.

Personally, I'd try to build a space shuttle with a rock and a railroad
spike, but that's the way I am.

CSC 



At 12:53 PM 10/1/00 -0400, you wrote:
>
>Hi All,
>
>I have been enjoying lurking in the background. I have just ordered a few
sets
>of achromatic lenses. A
>152mm and a 222mm. Can any of the list suggest a source of lens cells? Or
even
>some web site where
>construction of cells may be discussed? This is a whole new realm for me in
>that I have messed with
>reflectors mostly and my books that I have do not really address such a
topic.
>Any help is appreciated.
>
>Thanks
>Gary
>in Chicago.
>
>
>
>
>
>