APOD: When Rainbows Smile (2022 Mar 11)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4687
Joined: Fri Dec 04, 2009 3:27 am

APOD: When Rainbows Smile (2022 Mar 11)

Post by APOD Robot » Fri Mar 11, 2022 5:05 am

Image When Rainbows Smile

Explanation: /24/]Want to see a rainbow smile? Look near the zenith (straight up) when the sun is low in the sky and you might. This example of an ice halo known as a circumzenithal arc was captured above a palm tree top from Ragusa, Sicily on February 24. The vividly colorful arcs are often called smiling rainbows because of their upside down curvature and colors. For circumzenithal arcs the zenith is at the center and red is on the outside, compared to rainbows whose arcs bend toward the horizon after a downpour. True rainbows are formed by water droplets refracting the sunlight to produce a spectrum of colors, though. Circumzenithal arcs are the product of refraction and reflection in flat hexagonal ice crystals, like the ice crystals that create sundogs, formed in high thin clouds.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
Chris Peterson
Abominable Snowman
Posts: 16662
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by Chris Peterson » Fri Mar 11, 2022 5:38 am

Off my deck a few years ago, in context with some other common halos.
_
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

De58te
Science Officer
Posts: 468
Joined: Mon Sep 30, 2013 6:35 pm

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by De58te » Fri Mar 11, 2022 9:41 am

Hmm. I wonder why smiling rainbows are usually described as curved arcs, rather than described as curved bow shaped? Rainarcs anyone?

User avatar
XgeoX
Science Officer
Posts: 176
Joined: Tue Jun 30, 2020 12:57 pm
AKA: Uncle Rico

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by XgeoX » Fri Mar 11, 2022 12:11 pm

Stunning pic Chris.
Thanks for sharing!

Eric
Ego vigilate
Ego audire

User avatar
orin stepanek
Plutopian
Posts: 7610
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by orin stepanek » Fri Mar 11, 2022 1:05 pm

ArcoCircumzenitale_1024c.jpg
Today's APOD= A-OK! 8-)
I have seen circular rainbows from the spray of my garden hose! :mrgreen:
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

NCTom

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by NCTom » Fri Mar 11, 2022 4:05 pm

Beautiful picture, Chris. Out of curiosity, how long would the conditions last for those arcs to remain as they are? Seconds, minutes?

User avatar
Chris Peterson
Abominable Snowman
Posts: 16662
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by Chris Peterson » Fri Mar 11, 2022 4:14 pm

NCTom wrote: Fri Mar 11, 2022 4:05 pm Beautiful picture, Chris. Out of curiosity, how long would the conditions last for those arcs to remain as they are? Seconds, minutes?
IIRC, the arcs that day were around for a good hour. They kind of come and go in intensity at the thin clouds pass through.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Fred the Cat
Theoretic Apothekitty
Posts: 840
Joined: Mon Feb 22, 2016 4:09 pm
AKA: Ron
Location: Eagle, Idaho

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by Fred the Cat » Fri Mar 11, 2022 4:24 pm

Quite the juxaposition; cold weather and a palm tree! :brr:

But it makes me smile. :yes:
Freddy's Felicity "Only ascertain as a cat box survivor"

User avatar
MarkBour
Subtle Signal
Posts: 1253
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by MarkBour » Fri Mar 11, 2022 4:46 pm

Wow, I've never seen one of these before. The "refraction and reflection" linked article says "The circumzenithal arc, or 'smile in the sky' is fairly common but is rarely seen." I wonder if there is any weather data that could help one to know when such a wonder is more likely to appear.
Mark Goldfain

User avatar
Chris Peterson
Abominable Snowman
Posts: 16662
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: When Rainbows Smile (2022 Mar 11)

Post by Chris Peterson » Fri Mar 11, 2022 4:59 pm

MarkBour wrote: Fri Mar 11, 2022 4:46 pm Wow, I've never seen one of these before. The "refraction and reflection" linked article says "The circumzenithal arc, or 'smile in the sky' is fairly common but is rarely seen." I wonder if there is any weather data that could help one to know when such a wonder is more likely to appear.
I see them all the time. All you need is those thin ice clouds, which are common enough in most places in the winter. The reason they are rarely seen is probably the same reason so many common astronomical things are rarely seen: most people just don't look up very much. If you can see sundogs or the usual halo around the Sun, there's a good chance there's also a circumzenithal arc high in the sky above it.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com