Thursday, June 21, 2012

Arizona Aurora?

We are just back from a spectacular 5 day break from reality in Northern Arizona, mostly at the Grand Canyon for the annual star party there.  We've many previous posts regarding some of our time there on previous trips, so check here for a link to some of those exploits

On our way there last Friday (15 June), we stopped at the Bed and Breakfast of buddy Tom Taylor, proprietor of A Shooting Star Inn.  We'll write a separate post about our evening there, but what I'd like to cover tonight is a display of sky lights.  What looked like a thin layer of clouds moving in showed structure I've seen before from dark sky locations - airglow with gravity wave structures.  The main clue was the green color from oxygen emission. Shown here is a frame of several taken with a 16mm fisheye with a 1 minute duration, with only minor levels adjustments.  The bowl of the big dipper is coming into the upper left, Cassiopeia at lower right and Polaris, the North Star is upper right center.  It was a cool display, and like I said, the casual observers there thought they were thin clouds,  but the exposures show the green emission.

Then again just last night (19 June), on our last night of observing, showed a very similar glow and structure.  Again, the observers thought clouds were moving in, but again the exposures showed the telltale green emission.  I thought hard about it being aurora, but didn't see any characteristic rays, even though the display was very strongly centered due north.  Peaking right at about midnight as we were putting telescopes away from the night's public observing, after dropping Melinda and another observer off at the campground, I went back out to Yavapai Point and shot more frames from rim side for about a half hour.  I thought I could detect some pinkish or red color in some of the frames, but the structure and motion is consistent with airglow and gravity waves. 

I collected the 30 or so frames into a time-lapse and uploaded them into YouTube so you can see the structure and motion of the glow.  Interestingly, the structure was moving north on both nights, and the wind, which was very strong while taking the frames, was also towards the north.  In case the YouTube viewer doesn't load, go to this link to view on their website. Anyway, really cool stuff, but not aurora, which is pretty rare, even in Northern Arizona.  More posts about the events of the last week to come!

1 comment:

David A. Harvey said...

Nope - airglow! Nice post though.

Great pics too - wonderful examples of airglow.