Just after sunset on August 29, 1999, a large thunderstorm passed 85 kilometers to the south of my home in Hereford, Arizona. In fact, during twilight I had been admiring the lightning show that was illuminating the thunderhead. After finally giving up on the display in favor of dinner, I walked back to my house, taking one last look at the thunderhead before going inside. At that moment, I saw a strange light shoot above the thunderhead high into the sky. This may have been a single, narrow sprite, or it may have been something called a "blue jet." I did not get a good enough look to be sure.
The sighting caused me to rush around like a madman gathering video camera, tripod, and related gear. In the back of my mind was the recollection, probably based on some reading done years ago, that there were things such as sprites, they were rarely seen, and even more rarely videotaped, and that what I saw could have been sprites. After some lost minutes getting a tape together, I managed to videotape for about 30 minutes before local clouds encroached upon the display. During the first twenty minutes of the tape, I captured several sprites.
The images below are frame-grabs from that tape. The camera used was a Sony TRV-66 with the IR blocking filter removed. This camera is a typical consumer Hi-8 model. Mark Stanley informs me that most of the emission from sprites is in the 650-780 nm range, so the removal of the IR blocking filter probably helped to capture these.
You may be interested in visiting Stanley's website for more information about sprites. His website and correspondence has provided a crash course in sprite observation and (a little) science.
The images below are best seen at 800x600 or better.
Saving the best for first. This sprite appeared a minute and 36 seconds (T+1:36) after starting the tape. The extraordinarily bright sprite was esily seen as a dull red, upwardly-shooting light. My visual impression at the time was that the sprite had extended much farther up into the sky than it had, and caused me to worry that I had missed getting it on the tape. I adjusted the camera to point higher, and this cuts off the view of much of the thunderstorm in the following images.
This much fainter sprite was recorded at T+3:50. It was not seen visually because I was not looking.
This massive sprite display occured at T+6:53, and was accompanied by a smaller sprite just a few tenths of a second later (see the next image).
This sprite occurred just a few tenths of a second after the one in the image above, and contributed to the impressive nature of the display. With this one added to the mix, the whole sky appeared as though sprites were appearing in nearly instantaneous succession from right to left.
This sprite, at T+10:26, was possibly attenuated some by intervening clouds. It is the last sprite recorded, or at least the last that I noticed on the tape.
Images Copyright © Jeff Medkeff, All Rights Reserved, 1990
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