M-class solar flare | John Stetson

John Stetson
Location of photo
Falmouth, Maine
Date/Time of photo
April 16, 2012, 18:10 UT
90mm h-alpha filter, webcam
Here is an approximation of the speed of the April 16 solar flare and the size after 25 minutes: The attached image the April 16 M-class solar flare has been inserted into a full-disk (inverted) image of the sun taken on the 13th. 109 earths fit across the sun's angular diameter. It appears that in 25 minutes the flare extended out a distance of 40 earths from the sun's limb. 317160 miles was covered in 25 minutes. Speed? 761,184 miles per hour.