Saw someone wearing TWO-lenses glasses, about 1 inch apart, parallel

[David Combs]

Was going to a music performance; elderly woman behind me
had on glasses of a type I'd never seen before.

It was if she had two pair of glasses, one about one inch
out in front of the other pair.

I got a close look at them, and it wasn't some glued-up
hack job -- they were clearly manufactured from scratch
to be like that.

A: What is the generic name for that type of glasses?

B: What is it, acting as a telescope? (But as far
as I could tell it didn't invert the image.)

C: how long have these thing been around?

D: No -- stupidly, I didn't study the individual
near and far lens, to see if they were both
convex or concave or one of each.

Thanks!

David

[Mike Tyner]

You can google it as "galilean telescope." They've been around since, well,
Galileo.

It's a strong plus lens at the objective, and a roughly-equivalent minus
lens at the ocular. This combination magnifies without inverting the image.

I saw a consumer version of those glasses at a trade exhibit this weekend;
plastic pieces that collapse into a flat shape, but expand to make a pair of
lightweight telescopes with adjustable mag. The ones I tried on were about
2.5x.

-MT

"David Combs" <dkc...@panix.com> wrote in message
news:he2qfv$16m$1...@panix3.panix.com...

[Salmon Egg]

In article <he2qfv$16m$1...@panix3.panix.com>,
dkc...@panix.com (David Combs) wrote:

I think that the device you are talking about is a "lorgnette." See
Wikipedia. I find it difficult to believe that the single lens per eye
spectacles can be very useful. Galilean telescopes were used a lot as
binocular "opera glasses." Galilean telescope lorgnettes would be more
useful.

Bill

--
As the years go by, dying just before having to fill out a tax return has merit.