Aurora Borealis

Sunspot (10)652 unleashed a relatively minor M-class flare a few days prior to July 27, 2004, but it did give a nice direct blow to Earth's magnetosphere, and all of the required elements of a mid-latitude auroral event were in place. So I packed up the camera and Hayley and I drove north to get past a majority of the light pollution of Seattle, Everett and Marysville to a quiet country road west of Arlington.

We arrived at a very active period in the display, around 10:30pm with a very prominent hydrogen arc at 70 degrees and various pulsations, curtains and bright rays north of the arc. Though there was a fairly bright gibbous moon and growing haze from BC forest fires, the seeing was excellent. Any further north and one would have had very poor seeing due to the pall of smoke (you can see it as a dark band on the horizon).

As the day neared midnight, the hydrogen arc disapated and only a faint green glow could be seen north and northeast. Suddenly a very bright band appeared directly overhead, looking almost likea moon-lit contrail, however it was obvious from the rays that it was another arc. This curtain appeared as if it was braided in the photos below.

Hayley and I feel pretty lucky to have had the chance to view this rare event in Western Washington.

All photos were using manual timing with the remote cord, most at ISO 400. I kept the camera at f/8 to ensure it was sharply focused on the horizon. This combination, however, required longer exposures which blurred some of the details (rays, curtains). But I'm not sure I would have been happy with the grain at ISO800 or the DOF at f/5...

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