by gwrede » Sat Aug 17, 2024 5:13 pm
Like most of us, I was perplexed by the
blue wings of the star halfway up the picture, to the right of the Milky Way.
After some deliberation, my theory is that this photo was taken with a very wide angle lens. Such lenses tend to have quite a large lens at the front. Their absolute aperture is very small, because the F-stop value is proportional to the focal length. All this means, that a smudge on the lens impacts only a little part of the picture in wide angle lenses, while a smudge on a telephoto lens affects the entire picture.
So, it looks like there was a finger smudge at that particular spot. That smudge has to be done with a moving finger, because then it creates parallel grease ridges, which gives that kind of wings to bright objects. This is often seen in phone pictures with dirty lenses. (And because the phone camera is so little, the finger smudges tend to cover a good part of the entire lens.)
If Mr. Dury has used the very equipment he has in the photo in the BBC article (
https://www.bbc.com/news/articles/cz07l3glkdmo ), then this would be a plausible explanation.
Like most of us, I was perplexed by the [b]blue wings[/b] of the star halfway up the picture, to the right of the Milky Way.
After some deliberation, my theory is that this photo was taken with a very wide angle lens. Such lenses tend to have quite a large lens at the front. Their absolute aperture is very small, because the F-stop value is proportional to the focal length. All this means, that a smudge on the lens impacts only a little part of the picture in wide angle lenses, while a smudge on a telephoto lens affects the entire picture.
So, it looks like there was a finger smudge at that particular spot. That smudge has to be done with a moving finger, because then it creates parallel grease ridges, which gives that kind of wings to bright objects. This is often seen in phone pictures with dirty lenses. (And because the phone camera is so little, the finger smudges tend to cover a good part of the entire lens.)
If Mr. Dury has used the very equipment he has in the photo in the BBC article ( https://www.bbc.com/news/articles/cz07l3glkdmo ), then this would be a plausible explanation.