Friday, September 17, 2010

Pic of the Day: Aurora and Iridium Flare

Aurora and Iridium Flash
(Click)

"In the dream dusk
We walked beside a lake
We watched the sky move sideways
We heard the evening break"
- The Sky Moves Sideways by Porcupine Tree

Maybe a little explanation is in order. Obviously that's the aurora over a body of water (a side wash of the Chena River). But what's the bright streak? Not a shooting star, but an iridium flare. It's the antenna or solar panels of a satellite that just happened to be turned at the right angle to reflect the sun back to my camera as it orbits the Earth at 10-or-20 thousand miles per hour. They start out very dim or even invisible, then fade in to very bright as they move through just the right spot to reflect, then fade back out. This photo captures 15 seconds of movement as it fades out - it's moving left-to-right, even though your first impression is probably right-to-left.

Oh, the U-shaped constellation just above and to the right of the iridium flare, I believe that's Corona Borealis. Just FYI.

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