From the Heliospheric Imagers 1 field-of-view, the Coronal Mass Ejections then enter the Heliospheric Imagers 2 field-of-view.

The four synthetic movies of the ejections shown here are running ratios. On the top, synthetic observations from STEREO/Heliospheric Imagers 1. On the bottom, synthetic observations from the STEREO/Heliospheric Imagers 2. Once again, the movies are made for the spacecraft's configuration approximately 1 year after the launch.

The overtaking and merging of the leading edges of the CMEs would have been clearly observed by the Heliospheric Imagers 2 instruments. Associated with this merging, there is an increase in the observed brightness, which would have been observed around 11:00 UT on November 25 in STEREO/HI2-B and around 20:00 UT the same day in STEREO/HI2-A.