A Born again Planetary Nebula (Abell 78 in NB/LRGB, Cygnus)
Planewave CDK12.5; AP 1100GTO AE
ASI6200MM, - Antlia Pro RGB & 3.5nm NB filters
Ha/O: (33,25 x 360s exposures, Bin 1x1, Gain 200)
R,G,B: (30,30,28 x 240s, Bin 1x1, Gain 100)
Total Integration Time = 11.7 hours
Abell 78 is believed to be classified as a “born again” planetary nebula (PN), based on the theory as to how it got multiple shells. After going nova and creating its outer shell, sufficient hydrogen is thought to have fallen back onto the star to restart fusion for a period of time. Once this fusion restart ran out of fuel and second, inner shell was created. This inner ring, is mainly Helium, giving off a greener hue than the blue of the outer shell. The outer shell is also richer in red un-fused hydrogen. Further evidence for this second round of fusion is the fact that the central star’s spectrum is similar to a carbon rich Wolf Rayet star. Abell 78 is 5000 lys away and about 3ly across
This image of the PN was created as a composite of broadband RGB and narrowband signals – yielding the multiple shades of blue – rather than simply a narrowband image with RGB star superimposed. It is fairly bright, especially for its larger size so it was a treat to process. The most difficult part was placing the blue and orange/red stars symmetrically in the opposite corners to nicely frame the PN 😉.