Combining 15s interval whole-sky-camera photos to form a 4y spanning keogram

It took me a bit to understand that it's just the red line from the entire dome. It makes me a bit sad that so much information is discarded for these keograms. Isn't there a way to "peel" the image in such a way that the entire image ends up being the line? Like spiraling or something like that from the outer "rim" to the center point.

Nevertheless, it's the first time I've seen this and liked the project a lot. I've seen this from normal images, but not from such a fisheye lens.

Really cool project.

Edit:

Looking at https://victoriaweather.ca/keogram.php?photo=20120810.jpg how can this contain the entire landscape if only the center line is used, which is supposedly always the same line? I mean, the camera isn't rotating. Is this just another kind of view generated from the dataset?

But there are lots of images throughout the day.

Incredibly cool. I love this so much, both artistically as well as how it demonstrate the equation of time [1] -- the fact that the changes in sunrise and sunset are not symmetrical.

On the other hand, it's driving me absolutely crazy that he centers the image at 4:00 rather than midnight. Or maybe that's to show the shimmer of sunlight a little after noon on the right hand side?

I can't figure out why it's "bluest" closest to dawn and dusk. I'm guessing the exposure makes a huge difference, and obviously the night part is way more exposed than the daylight part, or else it would be much darker. Wondering if the camera used automatic exposure, and how much of the brightness of colors in the image are artifacts because of that? Also if he locked the white point hopefully?

[1] https://en.wikipedia.org/wiki/Equation_of_time

I was surprised there wasn't more of a line of red from sunrise/sunset.

It's probably because the composition algorithm takes a central line through each image (a line through the zenith), so it captures relatively few horizon-adjacent pixels that would highlight the reds of sunrise/sunset.

Pretty! But daylight savings time messes with the aesthetic.