I bring you the first version of Cassiopeia A, the remmant of one of the historical supernovae most studied by science, that of 1680.
This supernova apparently went unnoticed in its time and the references we have are vague, the clearest is from the astronomer John Flamsteed who cataloged a star (3 cas) that would be located 10' from the supernova remmant. This magnitude 6 star was always considered a Flamsteed error.
About the image, it is very weak and very small (barely 5 minutes of arc), it has hardly any emission in halfa and its highest emission is S2 and OIII. I have only managed to integrate 17x600 "in S2 and 11x600" in OIII.
The scheme used is unusual (R = OIII, G = OIII and B = S2) but I think it suits the object very well. However I will try other combinations. The goal is to maximize (very low) contrast and detail the filaments.
The telescope, an Astro-physics 130EDT and the camera a ZWO ASI294mm pro.