29 October 2003: Boulder, Colorado

This was the beginning of an incredible 3 nights of off and on major auroral activity. I was expecting the activity to begin close to dawn on the 29th, but around 11pm MST on the 28th, instruments onboard the ACE spacecraft measured a significant magnetic shock, and soon afterwards the Earth's magnetic field responded to the shock. I left home shortly before midnight for a 25-minute drive to an observing site in the foothills about 6 miles west-southwest of Boulder. A High Wind Warning was in effect for that area, and I had to deal with wind gusts of 30-40 mph at camera level at times (and worse gusts when I was hiding in my car). You can't really tell that from the photos, but you will see some power lines that I forgot about until I was already set up and shooting.

Despite the favorable conditions, it wasn't until close to 1am MST that the aurora started to get going. At about 1:10am, a greenish glow was slowly brightening low in the north, as depicted in the following photo:

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By about 1:30am, an arc had developed just above the terrain (which is just above the true horizon at this location), and was getting quite bright and obvious. This sort of feature is often a pre-cursor to significant activity:

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Then the floodgates opened. Rays started developing above the arc, and I suddenly noticed a vivid red area off to the northeast:

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Unfortunately, my 35mm focal length lens does not have a large enough field of view to capture what happened next. But, a bright curtain of light with embedded rays developed along the arc stretching more than halfway to overhead. The top 2/3rds of the activity was a vivid red color with green in the lower part. I missed some of this while changing to a new roll of film. If I had known that the spectacular part of the display was only going to last 10 minutes or so, I probably wouldn't have bothered with the camera. Anyway, this photo shows a brilliant red curtain to the northeast with hints of rays, and part of the green arc (turned more yellow in places due to the additive effects of red and green light):

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A bit later, here is a vertical view of a very bright red ray cutting through Leo the Lion, climbing out of the east-northeastern sky (the bright star to the right of the aurora is Regulus). From this fairly dark location, the photo barely does the color justice:

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After this, the display rapidly faded, and I left at 3:00am.

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File last modified: 01 December 2004

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