1. The stellar explosion represents the closest supernova of its kind seen in the last few decades.
2. As a result, images of the host galaxy of the supernova are visible at different times.
3. The uppermost circle shows the position of the supernova as it could have been seen in 1998.
4. The middle circle shows the latest position of the reappearing supernova in 2015.
5. The initial burst of light from the supernova illuminated the rings.