The maps represented here are not actually solar images, rather, they are a subtraction of two dopplergrams. The sun oscillates in a natural frequency of 5 minutes, therefore half of a solar oscillation is 2.5 minutes. The velocity maps have been computed by subtracting two dopplergrams separated 3 minutes apart...close enough. As a result, rotation of the sun has been removed, and relative velocities are left over, in the representation of red and blue regions.
Crimean Observatory | 60' Tower - MTW |
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May 12, 1996 - (15:10-15:13) UT | May 12, 1996 - (15:10-15:13) UT |