Last Night's Aurora Arrived Early, Tonight's the "Big" Night

Meagan Fitzgerald of Silver Bay, Minn. photographed a friend enjoying Sunday night's northern lights display from Caribou Lake in northern Minnesota. Fitzgerald observed the lights from 10:40 p.m. to 1:05 a.m. Monday morning. Meagan Fitzgerald

Well, yes, we did have aurora last night, but moonlight and clouds made it tricky to see. I suspected a diffuse glow low in the northern sky around 10:45 p.m. (CDT). Unfortunately, a distant bank of clouds masked the bottom 10° of the north, where you'd typically see the auroral arc. Without that arc and visible rays I couldn't confirm my sighting. Meagan Fitzgerald did a whole lot better!

This chart shows the Kp index, an indicator of potential auroral activity. Kp 5 equals a G1 minor storm; Kp 6 = a G2 storm. The strongest storming yesterday happened during the afternoon U.S. time (great for Europe), with a G1 storm (Kp 5) continuing through about 1 a.m. CDT. NOAA

I set the alarm for 3 and 4:45 this morning for another look. Clouds got in the way again. Others did see the northern lights but reported them as being on the faint side due to moonlight. Whether or not you were lucky enough to see the aurora last night, tonight's still the "big" night with a moderate G2 storm predicted between 10 p.m. and 1 a.m. (Sept. 28-29). Minor G1storming will continue through Tuesday night, Sept. 29. 

No matter when you're out looking there should be some sign of the aurora in the lower third of the northern sky all night. Due to moonlight, the minor G1 storms bookending the G2 may be difficult to make out. I'll often check for visibility by taking a time exposure of what I think could be the aurora. If it's green — bingo! But if it's blue sky, that's moonlight pretending to be northern lights. 

Good luck! I'll post images if the solar wind cooperates, the sky is clear and the aurora arrives on schedule. Sometimes so many things have to go right — but it's worth it!