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.
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.
Two solar ice halos spotted at lunch today.
The 22° halo around the sun is really bright and clear, and not that uncommon even in Los Angeles. I’ve seen so many that I still take photos, but I often forget to post them unless there’s something unusual about the view.
The circumhorizon arc below it, on the other hand, I’ve only seen a few times, usually fragments. It’s faint, but it’s the longest and least wispy of these arcs that I’ve seen (though the best was probably this one from 2010).
The lower one could be an infralateral arc. It wasn’t quite long enough to tell in person whether it curved upward or was parallel to the horizon, and it’s hard to tell how much of the curve in the photo is due to lens distortion. But according to Atmospheric Optics, they’re a lot rarer than circumhorizon arcs.
It’s cool to be able to get pictures of these with my phone. There was a time I’d run to get a camera and hope it wouldn’t fade first.
Saturation enhanced. It was really hazy!
Wispy sundog fragment (colors enhanced). The colors were really easy to see through my polarized sunglasses, but just faded into the glare without them. My phone barely caught it, but the info was there once I stretched the saturation.
A sundog looking like a ball of rainbow, and winter trees. The sun is out of frame to the right.