Conditions: 62 degrees; calm, very good seeing
Exposures: 30 min each through green and blue filters (10 min subs); 4 hours through Ha filter (15 min subs) for a total of 5 hours
Originally catalogued by George Abell as a planetary nebula, it soon became evident that it was actually a SNR. A relatively obscure supernova remnant, CTB1, is located in the constellation of Cassiopeia very near M52.
The filamentous edges are created during the supernova explosion when the shockwave slams into surrounding dust in the interstellar medium, ionizing gases such as hydrogen, as captured in this image
