A solar halo and sundogs surround the Sun on a cold winter day in Alberta.
I’m back home amid the snow and cold. The one celestial treat to such a clear but cold winter day is the appearance of sundogs and solar halos around the cold Sun.
This was this morning, with the low winter Sun above my snow-covered backyard, and the air filled with tiny ice crystals. You can see them as sparkly “stars” in the sky and in the foreground. Those crystals are refracting the sunlight and making the coloured “rainbows” on either side of the Sun called “parhelia” or sundogs. A faint halo encircles the Sun, topped by an upper tangent arc.
You can read more about halos and their origin at Les Cowley’s AtmosphericOptics website.
Here’s another view with a wider-angle lens. I’ve punched up the vibrance to bring out the fact that the shadows on such a day are not black or grey but blue, coloured by the intense blue light streaming down from the sky.
With these winter scenes, I wish all my blog fans and followers a very Merry Christmas, happy holidays and a very happy New Year. Clear skies to all in 2014!
– Alan, December 19, 2013 / © 2013 Alan Dyer
Here’s my first astrophoto from the land down under in 2012.
I’m in Australia for the solar eclipse, now two weeks away. With luck we will see the Sun disappear in a spectacular early morning event. But for now, here’s the Sun creating a solar halo shining in the sky over the icon of Australia, the Sydney Opera House.
After a couple of days in Sydney I head up the coast, collect and check out my telescope gear in storage for the last couple of years, and then begin the long drive up to northern Queensland and the rendezvous with friends … and the Moon’s shadow.
– Alan, October 31, 2012 (Australian date) / © 2012 Alan Dyer
We’ve certainly had our share (more than our share!) of snowstorms and blizzards so far this winter, though nothing like people down east have experienced. The one saving grace is that after the storm the sky often clears beautifully. In this case, on January 30, 2011 we had very clear blue skies, but filled with ice crystals of just the right shape (hexagonal) and orientation to produce a classic solar halo, with prominent sundogs on the 22° halo and a hint of an upper tangent arc, or is it an upper Parry arc? A trace of a circumhorizontal arc is also visible parallel to the horizon. Solar haloes are fascinating and often unique — each one can display a slightly different set of halo phenomena.
The website Atmospheric Optics gives great information and reference works.
– Alan, January 2011 / Image © 2011 Alan Dyer