Comet C/2011 W3 Lovejoy as it returns from its encounter with the Sun as seen in the STEREO C2 Behind imager (low resolution beacon images). (Comet Lovejoy bright dot just above the bright streak of comet tail bottom left, not the other bright dot top right). COMET LOVEJOY IS COMING BACK WHILE THE TAIL IS STILL GOING IN!!!!
Astonishing. You get a better idea of what is going on in the animation below.
Previous posts on the return linked here.