Naked eye rings?

OK, I have question; Tonight I was out walking the dog and boy let me tell you the sky was dark, as dark as I have seen it in a long time. will any way on with my question. I just got new glasses 8O and i was admiring Orion when I looked over at Saturn and for sure I thought I could see the Rings. Is it at all possible to see the ring with the naked eye? I know I'm going ti get some ribbing about the glasses ... and no they are bot bino's.

I have not looked at Saturn with a scope for some time so I have no reference to go by, but to me it looked like the rings were running on apx. 45 deg from lower right to upper left . ... right ? wrong?

Thanks

Bob

Robert, you are describing astigmatism or perhaps flares in the glasses.
Try to rotate your head and see if the "rings" follow your head, if so it is probably astigmatism.

Ok YES I KNOW I HAVE AN ASTIGMATISM! hens the new set of glasses, and they are not my first, I have had glasses for 20 years because of an astigmatism. But I got to tell ya, that when I look at other planets or stars I don't see the same thing as I do when i'm looking at Saturn. I know you can't "see the rings" but i'm I... could I be seeing defused light caused by the rings.

Bob

That's a very interesting question, Bob! Can't help but do a few estimates...

The diffraction limit of a fully dilated pupil (assuming D=7mm and lambda = 500nm) is lambda/D = 15 arcseconds, while the size of Saturn is 46 arcsecsonds. In other words, an ideal camera with a 7mm aperture will be able to see saturn as decidedly non-circular, perhaps even with a hint of a gap between the orb and the rings.

But a human eye is far, far from ideal. First, the rods and cones of the human eye are not sampled tightly enough. According to google, the average focal length of the human eye is about f=17mm, so the size of a diffraction-limited spot on the human retina is f*lambda/D = 1.2 microns. In the fovea, the peak rod density is about 150,000/mm^2 (thank god for google!), so that the minimum "pixel size" on the retina is about 2.6 microns. However, the retina is a color mosaic, so the brain must somehow bins triplets of different-color cones into a single color image "pixel", so that the real pixel size of an ideal eye is probably, oh, twice that size, or 5 microns. The size of Saturn on the retina, however, will be 46arcseconds*17mm = 3.8 microns. Right on the borderline, but not quite good enough.

And, all this assumes a diffraction-limited eye lens, which it most definately is not. If it was, stars would appear as geometrical points, or perhaps tiny disks if they saturate the cones on the retina. Maybe among the 90 billion humans that have walked the earth, there were a few freaks with abnormally large iris diameters, focal lengths, cone density, AND perfect lenses who could resolve Saturn. However, I don't think your eyes are freakishly large and perfect, Bob. No offense.

By the way, Bob, I assume you are myopic, which (I think) should make images on your retina even smaller, depending on how far your glasses are from your eyes. So, myopic people are at a (very slight) disadvantage of being able to resolve saturn (unless they are wearing contacts). The opposite is true for hyperopic people though. If you can focus on the sky with your reading glasses, the image on your retina should be (ever so slightly) magnified, perhaps just enough to resolve saturn! Unless I made a sign error