the object to the left is the sun having a CME. Both Stereos are in their own halo orbits and thus the images change based on where they are in their halo orbits, ditto Soho. Halo orbits are 1 million miles in diameter which changes which part of the sun is seen in those as the satellites move in their halo orbits.

to concept the halo orbit, hold your arm in front of you with a fist of your hand. your body is the orbit around the sun the satellite is in. now move your arm in a circle. That is the separate halo orbit of the satellite.


This may be the CME on SOHO you are seeing on HI1 behind. (blue) [link to sohowww.nascom.nasa.gov]