When I saw this object for the first time the initial thought was – It looks like a plasma ball! It caught my attention and it happened that it is in my reach. Still more than 5000 light years away from Earth in constellation Cancer, the Abell 30 is 2.1 arc minutes in diameter, big enough to image it with some details. The OIII signal is 15 times stronger than the Ha, filters I have. It happens that there is NII is much stronger than Ha, however no such filter around… So, it went near very top of my ToDo list and had luck to get some clear skies when this very peculiar nebula was still high above horizon.

And yes, it is a very peculiar planetary nebula - one of just three known nebulae called born-again planetary nebulae! The usual long story in short: The stars with masses around 1-8 solar masses live for billions of years in stable form, fusing hydrogen into helium. After that the core contracts and starts fusing helium into carbon, while the outer shells will start to expand forming a reg giant star. When the helium is gone the core shrinks more into very condensed and hot white dwarf which cools down another round of billion years till it reach cool stage named black dwarf… During white dwarf formation and life, the emitted energy forms strong solar winds which blows the outer shells and are forming a planetary nebula. 15-20 billion years into 4 sentences. Good compression ratio I think not lose-less though...   

Somewhere in the fourth sentence, the interesting part happened with Abell 30, so let's unzip this part a bit. When the white dwarf is forming the core is not uniform soup of carbon, there are layers with majority of different elements. A thin hydrogen layer, below is helium layer, follows carbon and even possibly a small oxygen core. The hydrogen is lighter and is flows up above helium, which flows up above carbon… So, the contraction of the carbon could lead to fusing it into oxygen, not very sable process as the core is not big enough, but it generates a lot of additional energy and it happens that it could be enough to heat the outer thin hydrogen layer to start the basic star fusion - hydrogen to helium giving a star rebirth. This is named “very late thermal pulse”. The pulses happen multiple times, possibly with different intensity on the collapsing core “surface”. The solar winds from the pulses are much faster and energetic from the already expanding ex-red giant outer layers. The clashes are forming interesting features by condensing and lighting different parts. The result is close to a plasma ball Different technology of course, but close look… 

One more interesting fact is that measuring the expansion speed to ~40 km/s gives the age of the planetary nebula to be around 12 500 years. The thermal pulses happened something like 850 years ago! It is almost real-time observation

The object can take more integration time in both OIII and Ha, it is curious what it shows in NII, however I’m happy with the result and hope you liked seeing it

https://www.astrophotography.app/