NGC 6894 is a lovely (in my opinion) and mostly typical planetary nebula about 5000 light years away in the direction of Cygnus, very close to our galactic plane. The central star, with a luminosity of 300 Suns and a surface temperature of 90,000 K, had serious mass ejections starting more than 10,000 years ago, and apparently is well on its way to becoming a white dwarf star (for example, a star the mass of our Sun would take 75,000 years to form a white dwarf after the mass ejection). That mass has now expanded in the main nebula to 0.5 light-years, excited by the intense radiation from that central star.
In addition,
Soker shows in deep Ha images from the Smithsonian Astrophysical Observatory's 1.2-m telescope on Mt. Hopkins that there are gas clouds near the nebula, which may have been stripped from the main nebula and also excited by that super hot central star. These clouds align in stripes that appear to be related to our galactic magnetic field, so in this regard, this in a very interesting nebula to understand the evolution of planetary nebula.
In my image, even extreme stretching did not show the striped nebulosity outside the main nebula, just a very dense starfield--stuck as I am at the bottom of a light-polluted sky, and at this point without an Ha filter. So instead I dialed back the stretch of the star field, and the associated bloated, bright stars in this cropped field, to emphasize the main nebula. The image was calibrated and stacked in DSS with 2x drizzle enabled, processed in Startools, with resolution enhancement and noise trapping of the nebulosity in Registax.
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