Moonset
Last evening was spent playing guitars with good friends in Paradise Valley, so no Friday post for three weeks now. I’m thinking it may become the norm - one day each week is nice to have as a break. It’s been unintentional thus far, but has allowed me a little needed leeway. I guess we’ll see next week…
Today’s image was taken about 7:15am this morning as the moon was setting in the west on my drive home from where I stayed in the valley. Dawn was fast approaching from the east, so a moderate, flat glow is visible across the landscape. I really like the vertical aura around the moon. I’m not sure what causes it, but you can see that the glow extends far higher than side to side, and extends downward quite brightly until being cut off from view by the horizon. I know streetlights will produce a vertical beam when it’s really, really cold outside, but I’m not sure if the physics at play is the same. Anyone have a theory or explanation?
Wonderful shot Cody! Sorry, no theory or explanation for the vertical aura.
Looks like it’s something called a light pillar, caused by hexagonal plate or column shaped ice crystals- Wikipedia
Wow, a light pillar, that makes sense. You’ll laugh, but I was trying to do a bit of research myself and Googled ‘light column’, but not ‘light pillar’.
Thank you for digging that up for me, and for both your comments, Diane!
I believe as Diane pointed out it’s a light pillar, which is an example of anisotropic specular reflection. That’s a impressive phrase which simply means reflection from grooves or particles that line up. It’s similar to the effect you get when the sun is setting on the sea, and you get a “column” of highlights directly under the sun, or when you look at an old vinyl record and you see highlight “spokes” reflecting nearby light sources. There’s an interesting discussion of the topic in the context of 3D graphics here: http://www.neilblevins.com/cg_education/aniso_highlights/aniso_highlights.htm
GREAT shot by the way
Hey Neil, thanks for the additional input on this. The link is great and I liked that it’s a tutorial - the companion bit on Anisotropic Reflections is pretty sweet too. That the surface the light is playing off of is really ice in the air…seems perfectly simple. I marvel at such things, I probably marvel too much. heh
Don’t ever stop. When we stop mavrvelling at the world is when we become jaded and cease to love life. And besides, can you really be a nature photographer without a well-developed sense of wonder?
Good point, Neil, I don’t suppose there’s much of a point to it all if I don’t appreciate the land by which I make my living through a veiwfinder. Thanks for your support!
Wow, really incredible shot and interesting timing regarding the explanations above. I wish I had seen it ‘live’. Also, nice job being there at the crack of dawn. So impressed…
I know, a morning shot, can you believe it!? I’m still expecting this week to find us out on some hill at dawn, snapping photos. Thanks for your comment, Vic.