Wednesday, 18 July 2012
Here we see the two dominant red spots surrounded by lesser violet ones. The boundary between is termed the inversion line - and separates fields of opposite polarity. A dark active region filament there with a ring of bright plage 'cocooned' the main spots. This was the site of major flares - though cloud and time-zone meant I saw only some modest C-class events. The group was to have a long-lived M class at the west limb five days later, producing fine post flare loops. This group is the second transit of AR11504 (June) - will there be a third in two weeks time?