Joseph Berkovitz Posted February 20, 2019 Share Posted February 20, 2019 I was out today for a brief beach walk in Devereux before paddling, and looked up to see the following amazing solar halo combination: My hand is blocking the sun to avoid frying the camera. There are four separate phenomena, at least so far as I can identify: 22º Halo (the circle around the sun with a dark interior and light rim) Upper tangent arc (the bow-shaped bright rainbow touching the top of the circle) Sun dogs (the bright spots to the left and right of the sun) Parhelic circle (the faint curved line intersecting the sun dogs and also the sun) I have never seen either an upper tangent arc or parhelic circle before. Quote Link to comment Share on other sites More sharing options...
BethS Posted February 21, 2019 Share Posted February 21, 2019 Amazing! The parhelic circle is new to me... Quote Link to comment Share on other sites More sharing options...
Sue Two Posted April 2, 2019 Share Posted April 2, 2019 Hi Joe That is so cool! Really is Amazing! Nice you protected your camera but I'm wondering how did you not hurt your eyes? Also what does the 22°refer to? Also is there, can there be, a lower tangent arc? If so , could have halos in every dimension:) 3D Halo Quote Link to comment Share on other sites More sharing options...
Joseph Berkovitz Posted April 2, 2019 Author Share Posted April 2, 2019 Sue, the original post has links to Wikipedia articles that explain the halos and their mechanisms much more clearly than I could, with some helpful diagrams. The piece on the tangent arc also includes a description of lower tangent arcs — yes, they exist. As for not hurting my eyes, well... I just try not to stare directly into the sun. Except when dropping acid. Quote Link to comment Share on other sites More sharing options...
JohnHuth Posted April 2, 2019 Share Posted April 2, 2019 The 22 degree is the minimum scattering angle. Ice crystals are hexagons, and the math works out with the index of refraction that the scattering angle of 22 degrees is the smallest, and also there's a broad minimum there for a variety of incident angles, so a lot of the light 'heaps up' close to 22 degrees. Quote Link to comment Share on other sites More sharing options...
Sue Two Posted April 4, 2019 Share Posted April 4, 2019 Thank you Joe and John I had looked at wiki briefly but didn't see the lower tangent and still couldn't figure out what the 22° refered too. I'll look again at the wikis since I'm confusing myself looking more at the picture. Why is the rim dark? Does 22° have something to do with hexagon angles? Guess I need to look up scattering angles and angles of refraction too. Anyway it really is a great picture, both for showing the scientific natural phenomena and artistically. It looks like Stonehenge in the foreground; maybe Stonehenge was built to see the halos Have a great day and don't drop anything Joe Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.