Time-Lapse: Watch the Sun Dip Down to the Swedish Horizon  

Bad Astronomy
The entire universe in blog form
June 15 2014 7:30 AM

Time-Lapse: Swedish Sunset

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Astrophotographer Göran Strand has taken quite a few gorgeous shots of the sky that I’ve featured on my blog, but nothing quite like this: a phenomenal time-lapse video of the Sun setting into the landscape in Sweden. You really need to make sure this is set to high-definition, and make it full screen.

Strand used a solar telescope that brings out details on the Sun’s surface, like sunspots, plages (bright regions around spots), and filaments. Note that in the video, those sunspots are about the same size as Earth!

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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He sped the video up by a factor of five, and added a bit of yellow to the Sun, but otherwise what you’re seeing here is real. He planned this long in advance, knowing that on June 8, as viewed from an arena in Östersund, the Sun would set behind a tower in Ås, a small village a few kilometers away.

I love how the Sun appears squashed, an effect due to our atmosphere when the Sun (or Moon) is near the horizon. The birds flying in front of it also added a nice earthly touch to an otherwise alien scene.

But what struck me the most about this video is the shallow angle at which the Sun sets; Strand was at a latitude of about 63° north. That far north of the equator, the geometry of the Sun’s path across the sky is different than what most of us see in June. It only gets about 50° or so above the horizon—compare that with where I live, in Boulder, Colorado, where the Sun gets a full 20° higher.

In Östersund, the Sun rises well to the northeast (at 4 a.m.!) makes a long, shallow path across the sky, and sets in the northwest at about 10:30 p.m. That makes the day more than 18 hours long (fully 3.5 hours longer than in Boulder), and it also means the Sun doesn’t get very far below the horizon before rising again. That’s why it seems to skim along in the video instead of diving down as it does in more southern locations.

Living on a big ball spinning and whirling around in space is weird. It produces all kinds of odd effects you might not expect, but which, amazingly, are entirely predictable. That’s how Strand was able to plan and make this video, and how I was able to understand it. And now you do, too.

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