Home » News & Blogs » The Sky Is Crystal Clear
Bookmark and Share
Astro Bob

The Sky Is Crystal Clear

1 Feb 2019, 21:58 UTC
The Sky Is Crystal Clear
(200 words excerpt, click title or image to see full post)

Sunlight refracted by prismatic ice crystals in high, thin cirrostratus clouds briefly painted the sky yesterday afternoon. An airplane and its contrail also joined the scene. Besides a halo and sundogs with wispy “tails” you can see the parhelic circle (arc through the sun connecting the sundogs), a Parry arc (rainbow-like arc tangent to the halo) and a diffuse upper tangential arc topping it. Bob King
Skywatching knows no hours. Wherever and whenever you tip your head back, a sight awaits. As I was dashing off to an appointment yesterday, I noticed high clouds and looked up toward the sun to see a brief but lovely display of atmospheric colors. Besides the often-seen halo, there were two sundogs on either side the sun — each with a tail! — a Parry arc, an upper tangential arc and a portion of the parhelic circle.
Two types of ice crystals cause most halos, sundogs and arcs – flat plates and columns or “pencils.”
After all the recent cold weather, a welcome warm front was on its way. Warm fronts announce their arrival with high clouds that gradually yield to lower-altitude types over the next 12 to 24 hours. Whenever you hear of ...

Latest Vodcast

Latest Podcast

Advertise PTTU

NASA Picture of the Day

Astronomy Picture of the Day