Tag Archives: halo

Tangents and Chords Across a Sun Halo.

Update: Someone on Flickr blamed this effect on aircraft emissions. No, these have been around long before aircraft. They’re caused by light refracting through ice crystals, which can be near the surface or high in the upper atmosphere. They get even more elaborate in places where it’s colder near the surface and more ice crystals can be suspended in the air – diamond dust in places where people are skiing, for instance – and super-elaborate in places like the arctic and Antarctica, which can support lots of ice crystals (and the south pole doesn’t have a lot of airplanes flying over it). More info: Atmospheric Optics: Ice Halos

There haven’t exactly been a lot of airplanes flying around here over the last few weeks, either – including the day I took this photo.

Glass Sundog

A bright sundog next to a glass-sided building.

A bright sundog next to a glass-sided building. The sun is off to the left out of frame. The sundog had a bit more color and more of the spectrum in it as seen through my polarized sunglasses, so I kind of wish I’d taken a shot through one of the lenses, but at least you can see how bright it was.

I haven’t adjusted the color on this image at all -– except for cropping, it’s straight out of my phone.

Bisected Halo

A circular halo around the sun, which is behind a tree. A contrail crosses the halo, leaving its shadow on the thin cloud layer below.

A clear 22-degree halo around the sun, bright enough that I didn’t have to adjust the image afterward. This is straight from my phone.

Even cooler: you can actually see the contrail’s shadow on the layer of cloud that’s producing the halo! The sun is behind the tree, and while the contrail pops out so it looks closer than the almost uniform layer, it’s clear from the shadow that the contrail is higher.