Re: ATM Light Shroud

[Bruce Swayze <swayze@europa.com>]

At 10:57 AM 8/15/97 -0400, you wrote:
>Hi All,
>
>One of the smaller pier mounted telescopes at the University of Florida
>is a 12" classical cassegrain.  Unfortunately, its open tube design is
>not very compatable with the light polluted environment in which it is
>currently located.
>
>Does anyone have a suggestion as to what lightweight material could be
>used to seal the tube from ambient light?  It would need to be flat
>black on at least one side OR paintable (something that will hold paint
>over time through temperature changes-- telescope IS in an
>observatory).  The material will have to be positioned inside the tube
>as there are several finder/guide scopes mounted on the exterior.  The
>inner diameter of the tube is approximately 13" so the material would
>need to have the required flexibility yet rigid enough to retain its
>shape over time.  The required length is at least 46", possibly longer,
>depending on whether I decide to extend the light shroud beyond the end
>of the tube or not.
>
>So far, we are considering rolled anodized metal, lightweight cardboard
>tubing, and thin sheet fiberglass.  Can someone tell me about the
>properties, available sizes, prices, distributors of Kydex?  Any other
>suggestions would be greatly appreciated.

Dear Richard,
I would consider a black material used to make backpacks.  I use this
material for a light shroud on my 15" truss-tube telescope, and it works
great.  It's a very durable nylon construction, and it's very black.  You
could use little patches of velcro on the tubings to hold it in place, and
it can be stretched tight enough to not sag into the optical path.  I even
use snaps on the front end of my tube to hold the front in place.  Sounds
to me like you could use snaps on the front and back of yours.  

An added advantage would be to be able to easily remove it for cleaning,
dust removal, working on the telescope, etc.  

I hope to have a photo of it on my web page soon.  I just took a roll of
photos that will be developed soon.  Check out my photo page at:
http://www.europa.com/~swayze/photos.html

Best regards,

Bruce Swayze
swayze@europa.com
http://www.europa.com/~swayze    Swayze Optical home page