Tag Archives: halo

Compass in the Sky

A circular halo of light around the sun, with a silhouetted traffic signal.

Two views of a 22-degree circular halo around the sun that I saw on a walk this afternoon.

Halos are a lot more common than I used to think. Then I started actually looking for them. Even on a warm day like today, there can still be ice crystals higher in the atmosphere of the right size and shape to cause a display like this (or even more complicated ones).

A circular halo of light around the sun, with a silhouetted jacaranda tree.

Usually I just go for a utilitarian, “got a picture of the halo,” but this time I tried about five different things to block the sun, trying to compose an interesting shot as well. I’m going to have to keep that up!

Dreariest Circumhorizon Arc Ever

Smudgy clouds, colors enhanced to bring out a straight rainbow effect.

I could barely see any colors in the cloud at all without my polarized sunglasses, and when I took a photo through them, I still had to bump up the saturation.

Thin clouds and contrails cross the sky. A bright rainbow-like ring circles a spot just out of view above the frame. A fainter rainbow-like line runs across the sky below it.I’ve seen several of these over the years. The brightest one was nine years ago, while the longest was just last year. It’s a solar halo caused by reflections inside ice crystals (near ground level or higher up in the atmosphere) that in theory could circle the entire sky parallel to the horizon. In practice, it’s rare for ice crystals of the right shape and orientation to cover more than a small area from any given viewpoint, so mostly people see fragments of them.

Smiling Sky

Wispy clouds with an upside-down rainbow near the top of the sky.

The last few weeks have been really good for halos. The first tangent arc I’ve seen, a clear circumscribed halo, the more common sundogs and 22° halos, and now a circumzenith arc, looking like an upside-down rainbow high above the sun, wrapping around the top of the sky.

I think this is the second I’ve seen, but the first was only a fragment.

Like all sun halos, they’re formed by light reflecting through ice crystals. And since those crystals can be in the upper atmosphere, you can see them even in warmer places like Los Angeles.

Taken with my phone through polarized sunglasses. Color and contrast enhanced.

Tangent in the Sky

A diffuse bright V-shaped light in the sky, slightly redder on the lower edge, with a faint arc of light extending downward from the center.

When I first started paying attention to solar ice halos, I read about tangent arcs. But this is the first time I’m sure I’ve seen one. The tangent arcs appear above and below the sun, branching out from the 22° circular halo (which you can see here, very faintly), and change shape depending on how high the sun is in the sky.

It was late afternoon, and the sun was behind the next building over. I ended up snapping a shot with my phone, wishing I could have grabbed a better camera, but the Pixel 2 caught a surprising amount of detail once I adjusted the brightness to bring it out. (No, the sky wasn’t this dark!). It’s a far cry from the G1’s photo of a very blue (and blurry) set of halos 10 years ago, or even the Galaxy S4’s colorless rainbows at sunset four years ago.