Supernova remnant 'Skilla'. /Courtesy of M. Drechsler, Y. Sainty, A. Soto, N. Martino, L. Leroux-Gere, S. Khallouqui, & A. Kaeouach

This is the appearance of the supernova remnant "Scilla" captured near the constellation Cepheus. Massive stars create heavy elements at their core and end their life cycle through a supernova explosion after millions of years. The traces of this supernova quickly fade, making it very difficult to discover, but amateur astronomers succeeded in locating Scilla by thoroughly sifting through photographic data. The red light comes from hydrogen atoms, while the blue light originates from oxygen.