Laser pointer: Evaluate optics

Hi all.

I hust got one of those green laser pointers. Playing with this
new toy, I "accidentially" happened to point it through my
binoculars (of course, no one were using the binos at the time).
When projecting the laser on the wall, there was an obvious
pattern of tiny dots surrounding the "main" dot.

I assume this pattern has something to do with the point spread
function of the binoculars. The question is: Can such a simple
test be used in practice to evaluate the quality of the optics?

Rune

On Oct 18, 2:51 am, Rune Allnor wrote:
Hi all.

I hust got one of those green laser pointers. Playing with this
new toy, I "accidentially" happened to point it through my
binoculars (of course, no one were using the binos at the time).
When projecting the laser on the wall, there was an obvious
pattern of tiny dots surrounding the "main" dot.

I assume this pattern has something to do with the point spread
function of the binoculars. The question is: Can such a simple
test be used in practice to evaluate the quality of the optics?

Rune

It's nothing to do with the point spread function. What you are
seeing are double bounce reflections off optical surfaces in the
binoculars.

www.richardfisher.com

Rune Allnor wrote:

Hi all.

I hust got one of those green laser pointers. Playing with this
new toy, I "accidentially" happened to point it through my
binoculars (of course, no one were using the binos at the time).
When projecting the laser on the wall, there was an obvious
pattern of tiny dots surrounding the "main" dot.





I assume this pattern has something to do with the point spread
function of the binoculars.

why would you jump to such an elaborate assumption. try any
diffraction grating and see what happens. good luck.


The question is: Can such a simple
test be used in practice to evaluate the quality of the optics?

Rune

On Oct 18, 12:51 am, Rune Allnor wrote:
snip
When projecting the laser on the wall, there was an obvious
pattern of tiny dots surrounding the "main" dot. . . . The question
is: Can such a simple test be used in practice to evaluate the
quality of the optics? - Rune

I do not know whether a laser can be used as an aid in evaluating the
optical quality of primary refractor objective or a mirror objective,
for example if one were somehow used in conjunction with a Ronchi
grating to project an image of the light passing through the grating
and onto a wall.

When passing a green laser pointer through a simple refractor, or when
projecting a green laser pointer beam for 1000ft onto a piece of
paper. I saw no similar projected dots.
http://members.csolutions.net/fisher...tst/index.html

- Canopus56

P.S. for lurkers. When using GLPs, safety comes first. Do not look
directly at a GLP through optics. If you do not have enough
experience to experiment with one - don't.