Shortly southeast of the prominent Bubble Nebula NGC 7635 in the constellation of Cassiopeia resides KjPn8 (see image version A, original). KjPn8 is a polypolar PN with a filamentary shell structure and another new forming Planetary Nebula (PN) in the center.

The Planetary Nebula KjPn8, also known as Kazarian-Parsamian 8, is a fascinating astronomical phenomenon. It was discovered in 1971 by M.A. Kazaryan and Eh. S. Parsamyan and independently discovered by Luboš Kohoutek in 1972. 

KjPn 8 is an extremely polypolar planetary nebula with a large-scale structure characterized by a huge biconical filamentary envelope. Repeated bipolar ejections in alternate directions over thousands of years have formed this peculiar nebula, whose relative size is about 14 x 4 arcminutes. The physical size is about 4.1 by 1.2 parsecs according to Wikipedia. This makes von KjPn 8 the largest known polypolar structure associated with a Planetary Nebula.

The complex nature of this unique object was first described in detail after analysis of Hubble Telescope (HST) images in this text: https://iopscience.iop.org/article/10.1086/309122/fulltext/. This paper elaborates that KjPn 8 may have formed from a binary system in which both stars had similar masses and entered the phase of forming a planetary nebula almost simultaneously, probably within 10-20 thousand years. This paper states that KjPn 8 may have formed from a binary system in which both stars had similar masses and entered the Planetary Nebula formation phase almost simultaneously, probably within 10-20 thousand years. The shell of KjPn8 is expanding at about 300 km/s fast enough to measure the proper motion of features in the giant lobes of the structure.

Interestingly enough, a new PN is forming in the center of the large structure. It can be seen as a bright red dot in my image. The formation of this structure is the most recent event in the complex formation history of KjPn 8. Only with the HST images could the nature of a central star of so far unknown type be revealed at this point. The star is surrounded by a compact nebular core, which in the images could be resolved into a young elliptical ring only 5.2" x 2.7" in size, slowly expanding at currently only 16 km/s. This ring is the ionized inner region of a larger structure of molecular CO and H, which has the same orientation as the ionized central ring.

I had "discovered" the interesting PN unexpectedly in my overview image of the region between the Bubble Nebula and the Lobster Claw Nebula made with 384 mm focal length. Because I was very fascinated by the object, I subsequently started to make a higher resolution image with a larger focal length (740 mm). However, I was unlucky with the weather and therefore had very little acquisition time. Therefore, both data sets were merged to give the post-processing more room for the depth of the image. The Ha and the OIII data are therefore a combination of the data from both focal lengths. The RGB stars are from the overview image with 384 mm alone.