June 17, 2012 Auroras from Pokegama Lake, Grand Rapids, Minnesota, USA
Submitted by Trond Knudegaard on June 26, 2012 - 9:09am
A pair of M-class flares erupted from sunspot group 1504 and were accompanied by some earth-directed coronal mass ejections (CMEs). When the CMEs hit earth on June 16, the interplanetary magnetic field (IMF) magnitude jumped to 40 nT with the earth-axis component ranging from +40 to -20 nT. With the relatively short nights near the summer solstice, there is not much time for shooting auroras, but I set up to get the sunset, hoping the auroras would appear as soon as it got dark.
It turns out they waited a bit, and as soon as they appeared, so did some clouds, which quickly overtook the field of view. Just when I was going to give up (and I actually reverted to shooting with my 24 mm lens), the clouds went away, and the auroras brightened up, making for a relatively decent shoot for the evening.
Canon 5d Mk II, one frame per 15 seconds (every 8 seconds during the best part), ISO 1600 (ISO 3200 during the 8-second segment), Sigma 15mm f2.8 fisheye lens.