Re: [ATM] ebay HUGE telescope lens calculations

[Woodchuck <djv@bedford.net>]

On Sun, 7 Nov 2004 rory123@bellsouth.net wrote:

> Hi:
> Bought this lens on ebay...Have an idea of what it can be used for...but don't want to wait until it gets here ...to measure it exactly.
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3850364518&ssPageName=ADME:B:BN:US:1
>
> Anyone know how get a closer estimate of lens characteristics?

Get it home and take it apart if it has more than one component
and you're comfortable with doing that.  You can measure the f.l.
of the positive elements directly, of the negative element (if any)
indirectly, and measuring the radii of curvature with a spherometer
can make a guess at glass type.

What is it?

"Lens is VERY powerful magnification".

Doesn't sound like an astro objective, which would be very much
like a piece of flat glass as far as "magnification" goes.
We'd expect a focal length in the range of 15 feet if this were
an astro objective of the usual type.

The mounting looks a little specialized;  if I had to guess,
I'd guess it was part of a collimator used for the adjustment
of binoculars, but only because I've been reading about them
lately.

Maybe part of a projection system?

Dave
-- 
        In each of us, there burns a soul of a woodchuck.
        In every generation a few are chosen to prove it.

_______________________________________________
ATM mailing list http://www.atmlist.net/