Re: ATM Home-made finder scopes?

[Anthony Stillman <atmer@flash.net>]

Ray,

>making your own finder...on a strict budget?

I suppose this isn't what you want but, personally, I've given up on finder
scopes.  I now use a Telerad.  That is, a zero power scope with illuminated
cross hairs (concentric circles) over layed and projected at infinity.  Of
course, I only have one.  I'd switch it from scope to scope when I
remembered.  Usually I'd end up thirty miles from home smacking myself in
the head with the palm of my hand.  Then brainstorm, a gun sight.  That is,
a small thin pointy thing glued to the front end of the tube.  A seemingly
largish washer glued to the other end of the tube. It helps to align the
sight with the optical axis of the scope.  Not that I ever forgot to do
that.

Now for what I suppose you wanted.  I've built a few small refractors.
Usually the objective was lifted from some otherwise broken thing.
Miss-collimated, ocean dipped binoculars (hey, it wasn't my fault, it was
the wave), yard sale scopes, ocean dipped camera lenses (now that one
really wasn't my fault).  The thing is, to include cross hairs you need a
real image plane in which to place them.  This means a Keplerian.  Hence an
inverted reversed image.  I find such finders a pain to use.  One of the
reasons I gave up on them.  You can add an inverter. This is already in a
binocular (usually a porro prism assembly).  An Acimi roof prism also works
well. And it bends the light path so you don't have to bend your neck.  As
for the occular.  A long f.l. Plossl, home made or otherwise.

If you can't wait for the "find", a good place to get surplus optics is
Surplus Shed <http://www.surplusshack.com/>


Anthony