Re: ATM Home-made finder scopes?

["Andrew Schott" <aschott@cfl.rr.com>]

I've never used finder scopes with reticles in them either.  Usually, the
process of "finding" is a coarse location to get an object into the field of
one of the lower power eyepieces you'll be using anyway.  I like finders
that are fairly low power, typically less than 7X and I like them "in-line"
as in no prism or bend in the viewing.  This allows me to use a technique of
centering that doesn't require a reticle.  Once I've found an object that I
want to view in the scope, I bring the finder in line with it.  When the
object is visible through the finder eyepiece, I open both eyes and look at
the object.  Usually this produces two views of the object, one magnified
and one naked eye, that are diverged by the amount of the misalignment.  I
simply move the scope in small increments until the images merge and this
usually places the object very close to the center of the main scope's field
of view.

Just something to consider when designing your finder scope :-)

----- Original Message -----
From: "Bob Bunge" <bbunge@ladyandtramp.com>
To: <atm@shore.net>
Sent: Thursday, December 27, 2001 10:07 PM
Subject: Re: ATM Home-made finder scopes?


>
>
>
> Ray Aldridge wrote:
>
> >My question of the day is this: how would you go about making your own
finder
> >scope, if you were a telescope maker on a strict budget?  I've spent many
> >happy hours roaming the web, but I haven't come across this subject (I
have
> >seen mention of using a BB gun sight as a unit finder.)
> >
> I've made many finders over the years using surplus 50mm objectives.  I
> once picked up a bunch from University Optics at Astrofest for cheap.
>  Just so happened that they fit inside 2-inch PVC pipe almost perfectly
> and some retraining rings made from sheet plastic worked well to hold
> them in place.  There are a number off the shelf plumbing fixtures that
> can be used to make the eyepiece end.  I suspect most 50mm finders will
> be similar.
>
> As to the eyepiece, I generally use old eyepieces.  The human eye is
> amazingly good at placing an object in the center of a circle.  If you
> use an eyepiece for which you can see the edges of the field stop, you
> won't have any problem with just a tiny bit of practice.
>
> Cheers,
>
> Bob Bunge
> Bowie, MD
>
> FYI, in the case of another reply there ain't no such thing as a "zero"
> power finder.  There can be a 1 power finder, like a Telrad, but never a
> zero power finder.  Your eye always sees the world/universe at 1 power.
>
> >
> >
> >Thanks very much,
> >
> >Ray
> >
>
>
>