I'm dreaming of a moon shadow

December 8, 2006 1:27 AM

Does anyone know what this phenomenon is called? It's not what I'd consider to be a moon dog or halo, but it sure was striking.
posted by pjern to Science & Nature (9 answers total)

Did you actually observe this? It really looks like a photography artefact. It could be some kind of crespular ray effect, though I have never seen it this way. You could check this site, or ask the site owner.
posted by swordfishtrombones at 2:05 AM on December 8, 2006

Indeed, looking at it I sorta presumed it had more to do with lens flare than an actual visible effect.
posted by antifuse at 2:19 AM on December 8, 2006

Best answer: I think it's a light pillar (also).
posted by RichardP at 2:22 AM on December 8, 2006

Some good examples of light pillars that look similar to the photograph in question can be found here.
posted by RichardP at 2:25 AM on December 8, 2006

Response by poster: Nope, not a lens flare...that's pretty darn close to what I observed. I think it's indeed a light pillar. Thanks all.
posted by pjern at 2:46 AM on December 8, 2006

RichardP: Those are some amazing clouds! I don't think it is a moonbow anyway - but you might want to look out for one of those now.
posted by rongorongo at 3:21 AM on December 8, 2006

What a spectacular, unique photograph.

I've seen quite a few light pillars during very fine ice-crystal snow storms, but never anything as striking or sharply defined as that.

It's interesting that the clouds in your photograph are intensely and extremely finely stratified; clouds bespeak structure in the air itself, of course, so I might be inclined to attribute the pillar in this particular case to low-angle reflection of light from boundary layers in the atmosphere which are very numerous and extremely close together, rather than the usual suspects: ice crystals.

Whatever the cause, I think you ought to try to find a way to to publish your shot more widely. It's really something.
posted by jamjam at 8:50 AM on December 8, 2006

Also, some great photos and exhaustive explanation of all atmospheric phenomenon on the Atmospheric Optics website.

geek alert: don't click on this link unless you want to be fascinated for hours.
posted by lonefrontranger at 11:09 AM on December 8, 2006

oh right... direct link into the section of Atmospheric Optics where they discuss how sun and moon pillars are formed
posted by lonefrontranger at 11:11 AM on December 8, 2006