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Suitable-Victory-105 OP t1_je2420f wrote

Reply to comment by MovingFjordward in Why from Earth do we see all these stars but in images taken from space we see none? by Suitable-Victory-105

Does this mean that we can see stars when the earth is blocking the sunlight?

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LaunchTransient t1_je25v89 wrote

If you are in any kind of shadow, yes.
It's basically the limit set by the dynamic range of the optical instrument viewing. Given that sunlight is 60 million times brighter than starlight, it's no wonder that it washes out.

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Micke_xyz t1_je2hg82 wrote

Now, let's take a moment to appreciate the wide dynamic range of the humen eye. Sure, if you look at the sun you will damage your eyes but it's still possible to see the contours of the sun, it's not a big white blur in that part of the sky.

And with that same "tool", we are able to clearly detect stars at night.

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LaunchTransient t1_je2jqny wrote

Yes, human eyes are amazing - but note that they cannot observe both phenomena at the same time. In sunlight, your irises constrict a lot and it's still dazzling - under a night sky they quadruple in diameter, so that's an 16:1 ratio when they fully dilate to when they fully constrict.

I doubt you could be able to gather enough light to see stars at full constriction, and your retina would be utterly overwhelmed if you tried viewing the sun with a fully dilated iris.

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PistolNinja t1_je2neiz wrote

You can mimic the same effect with a DSLR camera. Take a shot of anything with the aperture wide open, let's say say f1.2. Then without changing anything else, tighten the aperture to f5.6 or higher and the image will be WAY darker.

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