Un-magnified vision enhancement?

[rocketandroll]

Hi all

Been thinking about this recently and wondering if I'm just being dumb :-)

Last time I was out with a clear nught I was thinking... wouldnt it be awesome to be able to see the night sky brighter... but not magnified. Ie: if your eyes were,say, 100 X more sensitive... how much more you would be able to see.

That got me thinking... is there anything optically that does this?

Obviously binos capture far more light than the human eye but will always give at least some magnification. I guess what I'm after is binoculars with 3"+ lenses that have light gathering power 100 X greater than the human eye unaided, but which give an unmagnified image.

Is what Im talking about even viable? Let alone available? :-)

I just thought it would be incredible to see THAT much, details you cant see with the unaided eye, DSO's in context etc.

Just a crazy thought :-)

Ben

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[Capricorn]

Suspect that you would not get the effect you expect. I have seen the sky under dark conditions ~100+ miles between street lights. You cannot see many of the stars we are used to, they simply get absorbed into the background, Casseiopia is a good example, it more or less disappears.

If you had a 250mm mirror, FL = 1200 and could put a 100mm eyepiece in then I think you get about what you want.

Since 100mm eyepieces are not readily available then, same scope, focal reducer and the longest eyepiece you can get would come close.

A 0.5 reducer and 50mm plossl perhaps.

[earth titan]

How about light pollution glasses?

By posting here, can I claim patent, copyright or whatever?

[Ags]

Sorry, it won't work. The reason is that an optical system bundles the light going out of the eye lens into bundles with a diameter called the 'exit pupil'. You can calculate the exit pupil of a system by dividing the aperture by magnification. So a 200mm scope has a 4mm exit pupil at 50x magnification.

Obviously the lower the magnification, the larger the exit pupil.

Here is the problem: your pupil, fully dilated and dark adapted, is probably no wider than 5 to 7 mm, so that is the maximum size of exit pupil you can benefit from.

If you do the maths, you will see that a scope can only offer a maximum brightness for extended objects equal to the brightness given by the unaided eye! Stars, being point sources, are an exception to this rule. Basically, a big scope can show an object like a nebula bigger but not brighter than a smaller scope, at the same exit pupil.

[Ags]

There is always video astronomy... :-)

[Hypernova]

A zero-magnification system would not work for visual, the main problem being the exit pupil will be the same diameter as the primary mirror.

Taking an 8 inch/20cm mirror as an example divide the diameter of the mirror in mm by the magnification (200/1=200mm), the largest exit pupil our eyes can make full use of is on average 6-7mm.

[John]

You can just hold a filter like a UHC up and look through it. I've heard that under dark skies people have seen the North American nebula this way.

[Pug]

Night vision goggles (although it would turn everything green)