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X6.2 Solar Flare : Shockfront and Radio Sweep

September 9, 2005

Recording excerpt  1939:17 UT  to 1941:07 UT


Here is a one minute forty nine second audio recording of the flare's shockfront
and radio sweep recorded with a stereo radiotelescope at the frequencies of 22.222 MHz and 21.468 MHz.
If you listen close you can hear the burst hit on one stereo channel then hit the other channel  as the emission sweeps
down from higher to lower frequency. The velocity of this eruption was 959 kilometers per second.

Headphones strongly recommended for full stereo spatial effect.  And it is best played at moderate to loud volume.

The strongest peak comes at about 1 minute 20 seconds into soundfile.

Click below for specimen.


1.6 Mb   1 minute 49 seconds

Movies and visual record of event at


Extensive information on Type II radio bursts at    http://www.atnf.csiro.au/pasa/17_1/cairns/paper/node5.html

For more recordings

Thomas Ashcraft
35.50 N  -105.88 W
New Mexico  USA


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