York University has the graph

It shows possible eye damage at 10^7 cd/m^2, though the upper threshold exceeds the 10^8 level.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

It would.

Ah. I thought you were giving a figure for the level at which the cone/nerve system saturates, and so stops producing useful information about colour balance.

Grant Hutchison

Please VOTE!
No voters registration required!
No knowledge of science required!
No math required!
It's just your own opinion of how the Sun looks to you. 8)
[I'm doing a seminar and I'd like your view on the matter :wink: .]


It is a bit surprising this threshold is not easily googable. It wouldn't be that hard to establish it experimentally for each cone, right?

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Interesting comment in Kary Mullis's book, Dancing Naked in the Mind Field, where he says human vision is centered on green, because we evolved under the green forest canopy. I don't think I'd seen that on the BABB before.

I'm afraid that sounds like a "Just So" story to me ...
Most mammals have peak sensitivity in the blue-green region, mediated by just two sets of cones. The big evolutionary innovation made by old-world primates was to add a third, red receptor, which admittedly shifts the peak sensitivity more squarely into the green wavelengths, but more significantly (I think) lets them distinguish red from green - an extra level of colour discrimination that comes in very handy for fruit-eaters. A huge jump in colour discrimination seems much more of an evolutionary advantage than a slight shift in wavelength sensitivity.
There are also good physical reasons for animal vision to be centred around 550nm. Air is rather hazy in the ultraviolet, because of the preferential scattering of short wavelengths; shadows are not well illuminated in the infrared, because long wavelengths scatter poorly.
So if you want to be able to see into shadows and into the distance, with good resolution, using a simple lens system, you'll opt for an octave centred around 500-600m.

Grant Hutchison

yeah well Kary also says something to the effect of "biodiversity be d*rned, I'd stomp the last brown recluse into oblivion", he tends to get carried away with the moment.

I would presume it would require greater eye/brain ("retinex" as Lamb called it, IIRC) enhancement.

Chromatic abberation in the eye would be a bigger problem. However, for this reason apparently, the blue cones are not located in the central region but in the surronding region. Therefore, blue cones are fewer in number, though there is little loss in blue determination (if I understand it and I might not :-? )

Regarding dual color animal vision...
From Why the Sun appears Yellow

[I had presumed that orange hunter's apparel would look black to the deer but I could be wrong.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Bump.

Next week is my seminar. It would be great if you would be kind enough to take a quick peek at that bright star [Sun] overhead today and let me know what you think? [make sure it is 30 degrees or so above the horizon]

Thanks for being colorful!

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.