20X100 25x100 Binocular

Roland Christen wrote:
The point of putting your eye at the edge of the front aperture is that
you can very quickly evaluate whether the center and BOTH the edges of
the exit pupil are fully illuminated. If that is true, then the entire
field is fully illuminated.

Oops, my mistake--I mistook "front lens" for "eyepiece." The idea, then,
is that if the edge of the objective can see the center of the exit pupil
(which is delineated by the field stop?), then the center can see the
entire objective, and therefore the center is fully illuminated.

Correspondingly, if the edge of the objective can see the entire exit
pupil, then the entire exit pupil can see the entire objective, and the
entire field is fully illuminated.

Is that so?

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Roland Christen wrote:
The point of putting your eye at the edge of the front aperture is that
you can very quickly evaluate whether the center and BOTH the edges of
the exit pupil are fully illuminated. If that is true, then the entire
field is fully illuminated.

Oops, my mistake--I mistook "front lens" for "eyepiece." The idea, then,
is that if the edge of the objective can see the center of the exit pupil
(which is delineated by the field stop?), then the center can see the
entire objective, and therefore the center is fully illuminated.

Correspondingly, if the edge of the objective can see the entire exit
pupil, then the entire exit pupil can see the entire objective, and the
entire field is fully illuminated.

Is that so?

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

-Paul S. Walsh



"Chris1011" wrote in message
...

If you can see only one edge and center from the periphery of the front
aperture, then the field is only partially illuminated by the full front
aperture.
[etc, etc...]

Roland Christen

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

-Paul S. Walsh



"Chris1011" wrote in message
...

If you can see only one edge and center from the periphery of the front
aperture, then the field is only partially illuminated by the full front
aperture.
[etc, etc...]

Roland Christen

Ï "Paul S. Walsh" Ýãñáøå óôï ìÞíõìá
...

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

What's the little red circle? I can see the center of the exit opening, so I
assume that I can see the red circle, but I am not sure what the difference
between the green and red circles is.

-Paul S. Walsh
--
Ioannis Galidakis
http://users.forthnet.gr/ath/jgal/
------------------------------------------
Eventually, _everything_ is understandable

Ï "Paul S. Walsh" Ýãñáøå óôï ìÞíõìá
...

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

What's the little red circle? I can see the center of the exit opening, so I
assume that I can see the red circle, but I am not sure what the difference
between the green and red circles is.

-Paul S. Walsh
--
Ioannis Galidakis
http://users.forthnet.gr/ath/jgal/
------------------------------------------
Eventually, _everything_ is understandable

Ioannis wrote:
What's the little red circle? I can see the center of the exit opening, so I
assume that I can see the red circle, but I am not sure what the difference
between the green and red circles is.

I only see the field stop (and a sequence of baffles). As I guessed
before, if you can see the entire field stop from the edge of the front
objective, the entire field is fully illuminated. If you can see the
center of field from the edge of the front objective, then the center
of field is fully illuminated. I *think* that's the right interpretation
of the test.

In the case of my 10x30 Canon IS's, it appears the center is fully
illuminated (and so is a small part of the field surrounding the center),
but the edge is not. That effect is noticeable when using the binoculars
in the usual way, but it's hardly distracting.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Ioannis wrote:
What's the little red circle? I can see the center of the exit opening, so I
assume that I can see the red circle, but I am not sure what the difference
between the green and red circles is.

I only see the field stop (and a sequence of baffles). As I guessed
before, if you can see the entire field stop from the edge of the front
objective, the entire field is fully illuminated. If you can see the
center of field from the edge of the front objective, then the center
of field is fully illuminated. I *think* that's the right interpretation
of the test.

In the case of my 10x30 Canon IS's, it appears the center is fully
illuminated (and so is a small part of the field surrounding the center),
but the edge is not. That effect is noticeable when using the binoculars
in the usual way, but it's hardly distracting.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

My interpretation is that the red circle represents the full opening of the
eyelens (the lens closest to the eye when viewing) and I used Green to
represent the pupil of the human eye peering into the eyelens and centered
on that lens - but I also could simply be misunderstanding what Roland has
been describing.

-Paul S. Walsh



"Ioannis" wrote in message
...
Ï "Paul S. Walsh" Ýãñáøå óôï ìÞíõìá
...

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

What's the little red circle? I can see the center of the exit opening, so
I
assume that I can see the red circle, but I am not sure what the
difference
between the green and red circles is.

-Paul S. Walsh
--
Ioannis Galidakis
http://users.forthnet.gr/ath/jgal/
------------------------------------------
Eventually, _everything_ is understandable

My interpretation is that the red circle represents the full opening of the
eyelens (the lens closest to the eye when viewing) and I used Green to
represent the pupil of the human eye peering into the eyelens and centered
on that lens - but I also could simply be misunderstanding what Roland has
been describing.

-Paul S. Walsh



"Ioannis" wrote in message
...
Ï "Paul S. Walsh" Ýãñáøå óôï ìÞíõìá
...

Is it like this?? (see illustration)

http://www.nwlink.com/~filmdos/binovign.gif

What's the little red circle? I can see the center of the exit opening, so
I
assume that I can see the red circle, but I am not sure what the
difference
between the green and red circles is.

-Paul S. Walsh
--
Ioannis Galidakis
http://users.forthnet.gr/ath/jgal/
------------------------------------------
Eventually, _everything_ is understandable