Aurora OR Iceland 10/29-10/31

by Matthew Marcus

While you folks were marveling at red glows in the sky, I was in Iceland on vacation, on a tour which featured aurora-watching. We got more than our money's worth this time!

I won't go on about the scenic wonders (there are many) or seeing the original Geysir after which all geyser are named. I'll just describe, as well as I can, the auroras.

On Monday night, we were in a converted farmhouse called the Hotel Hekla, not too far from the eponymous volcano. It was cloudy, sleeting, rainy, and clear, changing every 15min to an hour or so. At times, we were looking at stars in one part of the sky while being sleeted on from another. We saw mostly arcs and rayed arcs in various parts of the sky. The only color visible to the eye was green, but some photographs (5-20sec exposure, 400ISO, f/2.8, 28mm) showed red and white. It was the sort of display that Icelanders consider rather routine. At one point, there was what looked like a green tornado apparently about to take a building to Oz.

Monday night was just a warm up. The following nights, we were in a nice hotel by the Ranga River, with almost no lights around. Despite the low level of light pollution, the sky never looked transparent. This was because of clouds some of the time, but mostly auroras. Our typical view of the Milky Way resembled that which you might get at MB or maybe even Houge.

On Tuesday, we started to get some real action. After some displays of arcs, rayed arcs, and curtains which appeared to be flapping in the solar wind, the sky suddenly lit up with very bright white displays arcing across the sky. Some of these showed pastel red and green colors at the fringes of the white. Great curlicues of light writhed across the zenith, at times appearing as if an invisible hand were writing them across the sky. What a show! This lasted for half an hour, and then subsided. I turned in around 0400. However, at 0500, people were seeing red glows and rays in the brightening morning sky. This turned out to be the leading edge of the burst from the X17 flare. Unfortunately, the main blob of solar particles hit during daylight, Iceland time (3 hours or so behind GMT). Still, we had no reason to complain!

The next night was mostly cloudy, with the clouds appearing bright as if the moon were out. I took pictures figuring that the color of the clouds, which was too dim to be seen naked-eye, would reveal what was going on. Well, I got more than I was expecting. Some pictures showed the clouds in fiery red. Others showed yellowish colors as if sunset were going on, except that the sun doesn't set in the South and it had already set some hours before in its usual place. Some of the pictures showed waterfall-like yellow, green, white and red displays visible through gaps in the cloud decks. The effect was rather like some of the more flamboyant landscape paintings of the 18th and 19th centuries, when artists were going a bit nuts with light and color in nature. I've never seen photos like these. Unfortunately, I don't have a negative scanner, nor have I set up a photo account.

But wait, there's more! Our last night must have been when that X7 flare hit. First, what looked like clouds but weren't appeared before the end of twilight. Next, we got bright green arcs once it got dark enough to see them properly. One of the tour members had predicted an Iridium flare just about at dinnertime. I went out in my shirtsleeves just before the predicted time, doing jumping jacks to keep warm, and was rewarded by seeing a bright flare in the midst of a green arc. Somebody else got that picture with a digicam. After that, it subsided for a while. Later in the evening, a red glow appeared on the S horizon. After that, somewhere around 11pm we got a real farewell display.

Curtains of light appeared, wavered, and disappeared over the whole sky almost all night. A curtain would appear to drop down on us from the zenith, followed by a wave of arcs at ~30deg from the zenith, then one at ~60 deg, giving the effect of tiers of curtains. The rays appeared taller than they had on Monday. It looked as if we were under attack from space, which of course is exactly what was happening. Our atmosphere defended us, as it always does. While this was going on, occasional rays would shoot up from the horizon and red glows would appear in various parts of the sky. Parts of the display would occasionally shimmer and pulse. This action kept up until the wee hours, gradually decreasing but never going away completely.

The local lore is that the normal display is green and that to see a red one is quite rare. We saw lots of red, naked eye as well as by camera. I gather that red is the signature of a powerful flare, which is why displays seen from our latitudes tend to be red.

The literature we were sent before the trip said to forget about trying to record the aurora with a camcorder as it's too dim. However, we found that the NightShot mode did pick it up. Some of the oxygen lines are deep red, in the range where the human eye is crapping out, but a CCD detects it handily.

On our way back to the airport, we all praised the travel agent for having the connections Up There to arrange two powerful flares for us.