This assembly represents the Sun observed in the purple
line of the ionized calcium (CaII-K) at the rate of an image
a year since 1998 until 2007. Every image is in fact a superimposing
of 2 observations made in approximately 2 weeks of interval, what
allows to show the activity corresponding to a complete rotation.
Heliographic North is at the top of the image and the
West is at the right. We shall note the importance of facules from 2000 to
2002 (maximum of activity) and the migration of the active regions since the
middle latitudes down to the equator (cf. Maunder's diagram). Click the image
to see it in larger size.
This second series is identical on the principle
but obtained this time in the Hα line. The processing highlights
more particularly the filaments whose distribution is much
more ample in latitude than that of sunspots or faculae. Cette deuxième
est identique sur le principe mais obtenue cette fois dans la raie H-alpha.
For all these images, the choice of July was expected
because I can get generally enough observations in this period of the year.
Here is the exact list of dates :