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Solar activity during cycle 23

 

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.

solar activity - cycle 23

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 série est identique sur le principe mais obtenue cette fois dans la raie H-alpha.

solar activity - cycle 23

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 :

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
CaII K
12 july 29 july 06 july 03 july 07 july 07 july 02 july 27 june 01 july 02 july
25 july 09 august 21 july 22 july 19 july 21 july 20 july 10 july 15 july 15 july
                   
12 july 29 july 06 july 03 july 07 july 07 july 01 july 27 june 01 july 02 july
25 july 10 august 21 july 22 july 19 july 21 july 20 july 10 july 15 july 15 july

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