Long-term evolution of the large CH close to the eruption site. Left: STEREO B/EUVI 195 Å image taken on January 25 at 02:36 UT showing the coherent CH stretching from slightly south of the solar equator to high northern latitudes. Right: STEREO A/EUVI 195 Å image taken on February 17 at 05:05, demonstrating the bifurcation of the CH into a northern and southern part, with the division occurring at lower latitudes.