Tag Archives: sundogs

Halo achievement unlocked: Spotted a parhelic circle.

Sun Halos over LA: Sundog, 22-degree circular halo, and parhelic circle

Sun halo fragments, clockwise from upper left:

  1. A sundog to the left of the sun.
  2. Part of a 22° circular halo to the right.
  3. Part of a parhelic circle (I think) in the opposite direction.

I spotted these just walking to lunch today, shortly after noon (well, DST noon). I wasn’t sure what I was seeing at first with the parhelic circle. It was clearly too smooth and regular to be part of the clouds surrounding it, but I’d never actually seen one before. Sundogs and 22-degree halos are a lot more common, even in the Los Angeles area.

After looking around for other halos, spotting the sundog and the 22°, and checking the height of both the sun and the mystery arc, I realized it was probably part of the parhelic circle, which when complete is a white circle running around the entire sky at the same altitude as the sun.

It wasn’t clear to the eye, but in the (slightly contrast-enhanced) photo of the sundog, it looks like the circle extends through it…which suggests to me that maybe I have seen it before. I’ve seen what I thought were elongated sundogs, but maybe they were sundogs with small fragments of this halo.

Halos like these are caused by reflections of sunlight inside ice crystals, sometimes near the ground and sometimes, as in this case, up in the sky. Different shapes, sizes and arrangements of crystals create different paths to the eye, which make different halos.

Look up in the sky!

You may never seen a halo around the sun or a sundog next to it, but they’re actually quite common. You just have to look up. (Just don’t stare at the sun!) I usually keep an eye out for sun halos whenever there’s a thin cloud layer, since there usually aren’t ice crystals near the ground in LA, but the upper atmosphere is a lot colder.

I actually wasn’t looking for this halo. I just happened to look up toward the tree across the street and *wham* – there it was.

Just one day later, I saw a fainter halo while walking to lunch…and noticed this rainbow-like sundog off to the right of the sun. I tried to take another shot with my sunglass lens in front of the phone, but fumbled it, and by the time I fixed the settings, it was gone.

You don’t even have to be outside — a few weeks ago I posted a view through an office window. But you do have to look up once in a while!

Sundog, Saddleback, Clouds and Dust

Seen from near LAX through an office window. The Santa Ana winds have cleared away the smog, making the view unusually clear (until the dust takes its place).

The sundog near the top of the frame was definitely in the sky and not on the window, and was visible no matter where I moved — I actually had to adjust the angle to avoid a reflection on the window that would have drowned it out! Timing is everything, though: I went to grab a cup of coffee from the break room right after this, and it was already gone when I got back.

Sundog above juniper trees.

juniper-sundog

This stood out starkly when viewed through my polarized sunglasses late Friday afternoon, but disappeared completely into the glare without them. I had to put my sunglasses in front of my phone to get this, and even then I enhanced the color saturation before posting. The sun is off to the left.

Elongated Sundog and Contrail

I got off the freeway to catch the train out to the office last Tuesday morning, and saw this incredibly bright sundog off to the east. I couldn’t get a parking space, so I had to drive the rest of the way, but I did get a couple of photos.

The sun is off-frame to the right.

I’m not sure why the bright patch was so elongated and well-defined. My guess is that a smaller cloud in the foreground happened to be in exactly the right spot to reflect the sunlight.

I had to shorten the exposure in order to actually get some detail on here, like the bit of color spectrum in the middle.