Three synthetic movies of the ejections are shown here, all are running ratios. On the top, synthetic observations from LASCO C3. On the bottom, synthetic observations from the 2 STEREO Heliospheric Imagers 1 (1 year after the launch of the satellites).

As the ejections reach about 15 solar radii (still in the field-of-view of LASCO C3) they enter the field-of-view of the Heliospheric Imagers 1. Since this instrument observes away from the Sun with an offset angle towards the Sun-Earth line, the ejections do not appear as half an halo (front view) but there is also a component similar to a view from the side (limb view). This makes the determination of the "real" speed of the ejections from STEREO HI1 easier than from LASCO C3, since the projection effects are smaller. The difference in the propagation velocity of the CMEs in the different quadrants of the heliosphere is also very clear.

Due to a difference in speed and deceleration, the second ejection is "catching up" with the first one as can be easily seen at the end of the HI1 movies. In the STEREO B (bottom right) movie, the first two ejections are in the process of merging starting around 06:00 UT on November 25. No such things is apparent in the STEREO A (bottom left) movie.

From there, the ejections will be observed by the STEREO Heliospheric Imagers 2.