On Tuesday, December 7, 2021 at 12:48:48 AM UTC-7, StarDust wrote:
> On Monday, December 6, 2021 at 4:40:15 PM UTC-8, Chris L Peterson wrote:
> > On Mon, 6 Dec 2021 10:17:22 -0800 (PST),> wrote:

> > >What size binocular?

> > 8 X 56.

> 56?
> Interesting size!
> Either 50 nor 60!
> LOL!

56 may not divide by 10.

56 does, however, divide by 8. It equals 8 times 7.

So the exit pupil of the binocular is exactly 7mm; thus, the binocular is a "night glass",
like a 7 x 50 binocular (here they gave it an extra 1mm of aperture, even though it only
needed to be 7 x 49).

8 x 56 is actually quite a common and normal size of binocular.

John Savard

WONDERFUL NEWS!!!!!!!!!!!
Another Chicom launch with new spy satellites added:
https://www.youtube.com/watch?v=kGtnvlQoyaw

On Tuesday, December 7, 2021 at 4:50:14 AM UTC-8, Quadibloc wrote:
> On Tuesday, December 7, 2021 at 12:48:48 AM UTC-7, StarDust wrote:
> > On Monday, December 6, 2021 at 4:40:15 PM UTC-8, Chris L Peterson wrote:
> > > On Mon, 6 Dec 2021 10:17:22 -0800 (PST),> wrote:
>
> > > >What size binocular?
>
> > > 8 X 56.
>
> > 56?
> > Interesting size!
> > Either 50 nor 60!
> > LOL!
> 56 may not divide by 10.
>
> 56 does, however, divide by 8. It equals 8 times 7.
>
> So the exit pupil of the binocular is exactly 7mm;
Right!
But for an older person's eye pupil only opens up to 4-5 mm max .
So 2-3 mm of light is wasted?

On Tuesday, December 7, 2021 at 10:50:26 AM UTC-8, StarDust wrote:

> But for an older person's eye pupil only opens up to 4-5 mm max .
> So 2-3 mm of light is wasted?

The price you pay for getting old! You either deal with it or quit the hobby... I choose to just deal with it...

On Tuesday, December 7, 2021 at 1:50:26 PM UTC-5, StarDust wrote:
> On Tuesday, December 7, 2021 at 4:50:14 AM UTC-8, Quadibloc wrote:
> > On Tuesday, December 7, 2021 at 12:48:48 AM UTC-7, StarDust wrote:
> > > On Monday, December 6, 2021 at 4:40:15 PM UTC-8, Chris L Peterson wrote:
> > > > On Mon, 6 Dec 2021 10:17:22 -0800 (PST),> wrote:
> >
> > > > >What size binocular?
> >
> > > > 8 X 56.
> >
> > > 56?
> > > Interesting size!
> > > Either 50 nor 60!
> > > LOL!
> > 56 may not divide by 10.
> >
> > 56 does, however, divide by 8. It equals 8 times 7.
> >
> > So the exit pupil of the binocular is exactly 7mm;
> Right!
> But for an older person's eye pupil only opens up to 4-5 mm max .
> So 2-3 mm of light is wasted?

In terms of light gathering power that would work out to be equivalent to only an 8x40 binocular that is going to be lighter and more compact. There are other factors that could sway one's decision between the 8x56 and the 8x40.

On 07/12/2021 18:50, StarDust wrote:
> On Tuesday, December 7, 2021 at 4:50:14 AM UTC-8, Quadibloc wrote:
>> On Tuesday, December 7, 2021 at 12:48:48 AM UTC-7, StarDust wrote:
>>> On Monday, December 6, 2021 at 4:40:15 PM UTC-8, Chris L Peterson wrote:
>>>> On Mon, 6 Dec 2021 10:17:22 -0800 (PST),> wrote:
>>
>>>>> What size binocular?
>>
>>>> 8 X 56.
>>
>>> 56?
>>> Interesting size!
>>> Either 50 nor 60!
>>> LOL!
>> 56 may not divide by 10.
>>
>> 56 does, however, divide by 8. It equals 8 times 7.
>>
>> So the exit pupil of the binocular is exactly 7mm;
> Right!
> But for an older person's eye pupil only opens up to 4-5 mm max .
> So 2-3 mm of light is wasted?

Linear dimension affects resolving power.

It is the area of the lens lost that matters for light grasp.

pi(R^2-r^2)

In this case for 7mm exit pupil with iris diameter 5mm.

pi(49-25)

So about half of the light captured by the objective lens is lost by the
light cone hitting the iris rather than the retina.

--
Regards,
Martin Brown

Leonard the 'comet of the century' becomes an astronomical
disappointment!!!!!!!!!!!!!!!
The prospect of such a bright comet sents the mainstream media into a
frenzy.
https://www.youtube.com/watch?v=4EoAHdwGBvU