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Comment by pugworthy | Hacker News Reader

During the recent aurora activity, I took multiple pictures from my back yard using my iPhone 15 Pro to see if it would show up. It didn't, but I was blown away by just how many stars were visible in the resultant photos. I need to go back and see how many Messier objects I can get to show up that way.

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The aurora was visible for me and it was remarkable how much better it looked through my phone. What were faint grey lines, at first not even something I would think was the aurora if it were any other day, came out as vibrant green and purple through the screen; reminded me of the They Live glasses.

The aurora really surprised me that way: I had only seen pictures before, and never guessed so little of it would be visible in real life. The effect is definitely better seen through a camera!

That's always going to be true of the night sky though -- and is the goal of astrophotography.

That's not to say that there aren't some amazing aurorae that you can experience with the naked eye, if you go closer to the poles (well, practically just the Northern one) on a good night you won't need a camera!

Even for those, presumably a camera will catch more stuff in the background though.

Conversely, my experience with the 2016 and 2024 total solar eclipses was the exact opposite. I was expecting reality to look less impressive than eclipse photos, but nope. You look up in the sky there's a damn ring of fire up there.

I looked up and saw the deep blue sky, and stars, and a Black Hole Sun... An unnaturally dark void, surrounded with light

Quite unnerving

Aurora magic is possible only because of computational photography. There is no way a phone camera, at the base level, can see more than an eye.

Why do you say that? Or do you call long exposures computational?

They are not long exposures. If they are, you would see star trails, because earth is spinning.

You absolutely see star trails on iphone night mode photos when setting exposure to 10s or more. For aurora, 10s is way too much though, 1-3s seems right and is what the iphone allows to do when not on a stable surface or tripod.

Whoa, you're just way off base here. You can take a long exposure and avoid star trails depending on a couple of factors, primarily the focal length of the lens. The longer the lens, the less time it takes to start seeing trails. The wider the lens, the longer you can take. I've taken up to 45s exposures with a 20mm lens on a DSLR with no trails. Since most lenses on camera phones are typically wider angle, the limiting factor is having a support to hold it for longer exposures.

Rather depends upon what you consider "long" to mean. The sun moves about 15 degrees per hour and the angular field of view on a zoomed iPhone 13 shot is about 23 degrees (according to a blog). 12MP resolution so crudely moves about one pixel per second. A ten second exposure is certainly long compared to the light gathering drive by the eye, but a ten pixel elongation of the blob of a bright star won't be very obvious, may be rather less than the smearing caused by atmospheric "seeing"

Some sources (https://lweb.cfa.harvard.edu/webscope/activities/pdfs/eyeTel..., page 7) say the human eye's "exposure time" is around 1/15th of a second. So a 1 second exposure is 15 times longer and won't see star trails, at least not at normal zoom levels.

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