Huge Sunspots

Martin wrote:

This latest appearance, the ring (or horseshoe), seems to reinforce my
unexpected conclusion that sunspots/groups are far less stable than
they were 2 or 3 years ago - they develope and fade with greater
rapidity.

They are and they aren't. Active regions can have lifetimes measured anywhere
from days to over a month. Typically, they do not last much more than one
solar rotation, although a few large ones have lasted longer. These
Gamma-Delta groups are known for their activity and are the frequent site of
major solar flares. The "ring" which you have seen is merely an odd-form of
group and not necessarily indicative of life span or spot stability. If you
want to know more about how active regions develop, you might want to read the
article OBSERVING THE SUN IN H-ALPHA on the website of the Prairie Astronomy
Club (see URL below). Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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