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Recent Auroras Over Central Illinois, USA

24 May 2000

Alarm 1: 0309 UT (10:09 p.m. CDT May 23)
Alarm 2: 0334 UT (10:34 p.m. CDT May 23)
Alarm 3: 0350 UT (10:50 p.m. CDT May 23)

On this night I had been out all evening and did not return until 11:30 p.m. CDT, by which time the three alarm messages were waiting on my answering machine. (At the time I had no computer at home, but set up a modem at school to leave me voice messages.) I was immediately suspicious, because a "one, two, three" in rapid succession can indicate a problem with stray light at the detector. A quick drive to campus, however, revealed a K index of 7: This was no drill!

After speeding to my favorite dark site, I watched and photographed the aurora until 3 a.m. It was diminished somewhat by the gibbous moon that rose at 12:30 a.m., but this was still the best display I had seen so far, and the first with more than one color visible. A bright green curtain glowed at the horizon with deep red above, at times extending visually beyond Polaris. Gradual motion was also visible as rays shifted back and forth.


Photos: Attractive, red-topped aurora extends high into the sky. After moonrise, purple aurora appears. Kodak Elite Chrome 200, unknown exposures at f/2 (50 mm) and f/2.8 (28 mm). A portion of the POLAR spacecraft visible light image taken at 2:35 a.m. CDT reveals that the southern edge of the aurora was directly over Chicago.

16 July 2000

One of the biggest geomagnetic storms of the solar cycle, and a huge aurora... yet somehow this display managed to avoid most populated areas at night. For potential viewers in North America, the circumstances could not have been worse: Less than a month after the summer solstice, with nights still very short; a full moon on that very night; a CME that arrived in the morning daylight hours, allowing the main phase to wind down just as darkness finally arrived. Despite this, a patient observer could spot some leftover activity.

This is the only event in the gallery for which no aurora alarm was issued. Given the bright moonlight, it didn't stand a chance. If I had known how weak and short-lived the display would be, I would have stayed home too...

Photos: Unseen? Almost. A full moon illuminates the foreground as fleeting red rays appear in Ursa Major. Total duration of this display was less than 15 minutes. Kodak Elite Chrome 200, unknown exposures at f/2.

12 August 2000

Alarm 1: 0809 UT (3:09 a.m. CDT)

The "Perseids aurora" of 2000 was quite unexpected, but many amateur astronomers saw it anyway because it coincided with the only dark (moonless) hour during the peak night of the Perseid meteor shower. I should have gone out into the country, but decided to watch from my front porch instead. There the display appeared faint; people at dark sites saw much more.


Photo: A solitary purple ray emerges from the light pollution of Champaign's north commercial district, as seen from my front yard. Kodak Elite Chrome 100, unknown exposure at f/2.

31 March 2001

Alarm 1: 0439 UT (10:39 p.m. CST March 30)
Alarm 2: 0448 UT (10:48 p.m. CST March 30)
Alarm 3: 0457 UT (10:57 p.m. CST March 30)

On March 29, a large solar flare (X-ray class X1.7) from active region 9393 ejected a cloud of plasma that reached Earth just as the sun was beginning to set across North America---perfect timing for the aurora. Severe geomagnetic storming lasted all night and produced an aurora visible across the entire United States and into Mexico wherever the sky was clear.

The aurora detectors in Illinois and Washington recorded the most active portion of the display from 0500-0900 universal time. During these hours, the magnetic K-index hit 8, then 9, the highest possible reading:


Here are some of my observations written the following day:

... After escaping the city lights, we pulled over to scan the sky at about 0530 UT (11:30 p.m. central). At that point only the brightest stars near the zenith were faintly visible through the thick haze. A fuzzy band of aurora could still be discerned, high in the north, and I thought I could detect some of the brighter ray structure at times. I began to explain (somewhat apologetically) to my friend what he could have seen had the sky been clear.

As midnight approached, the haze/clouds seemed to be thinning slightly, and I thought I could detect some bright, fuzzed-out rays reaching to near the zenith. We decided to head further north since our dark-adapted eyes had become more sensitive to the light pollution from Champaign-Urbana in the southwest.

Fifteen minutes later, as we were just leaving the little town of Royal, I decided to pull over and stick my head out the window for a second... WOW!!! Suddenly it was quite clear overhead and we could see bright red veils and whitish rays all around, extending upwards to a brilliant corona display! After gawking in amazement for a couple minutes, we tore ourselves away just long enough to drive down the road a few miles where it was darker.

From this new location we watched the peak of the display, which lasted for perhaps 30 minutes (~0600-0630?) although it seemed much less. The sky was almost totally clear now and the aurora was very bright, mostly red and white at this stage, and all around us extending well down into the southern half of the sky. Near the zenith, at the vanishing point of the local magnetic field lines, the corona was constantly changing in shape...

As this stage began to wane, we noticed the flaming and pulsating aurora. Brightenings in the broad rays extending to the zenith would shoot upwards, kind of like a "Jacob's ladder" high voltage spark machine. Eventually, the whole region near the zenith broke into isolated blobs of dim, whitish aurora, which were flickering rapidly. This went on for a long time, maybe an hour.

After 0730 UT, the dominant aurora was a broad, very bright, green arc in the north. At first it was diffuse and quiescent, but gradually the lower edge gained definition and sharp rays became visible, extending to near the zenith... Eventually this arc-turned-curtain began to distort into a wavy structure, with lots of embedded rays. There was definite motion, but nothing fast... Finally at 0830 UT I packed up and drove home with this "classic aurora" still hanging beautifully in the northern sky.

Top, left to right: Mixed green and red rayed veils; broad green arc to the north, after peak of activity. Bottom, left to right: An observer and truck are silhouetted against bright red aurora, which is also reflected from the truck roof; intense red diffuse aurora in Ursa Major; overhead corona display; heavily processed corona display showing more rays. All photographs: Kodak Elite Chrome 100 pushed to ISO 200, 20-60 second exposures at f/3.5 (wrong camera...).

6 November 2001

Alarm 1: 0233 UT (8:33 p.m. CST November 5)
Alarm 2: 0247 UT (8:47 p.m. CST November 5)
Alarm 3: 0253 UT (8:53 p.m. CST November 5)



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Last modified 23 November 2001 by haunmarabbitketeuaardvarkorg replace animals with punctuation