PN G100.4+04.6/PM 1-333 is listed at NED as a possible planetary nebula though the most recent paper on it from 2009 considers it has proven it to be a true planetary nebula. In the article, they refer to it as PM 1-333. The abstract has this to say about it: "PM 1-333 is an extended planetary nebula with a high-excitation (He II?4686/Hß up to ~ 0.9) patchy circular main body containing two low-excitation knotty arcs. A low Ne([S II]) of ~ 450/cm3 and Te([O III]) of ~ 15000 K are derived for this nebula. Abundance calculations suggest that PM 1-333 is a type I planetary nebula. The lack of a sharp shell morphology, low electron density, and high excitation strongly suggest that PM 1-333 is an evolved planetary nebula. PM 1-333 also shows two low-ionization polar structures whose morphology and emission properties are reminiscent of collimated outflows. We compare PM 1-333 with other evolved planetary nebulae with collimated outflows and find that outflows among evolved planetary nebulae exhibit a large variety of properties, in accordance with these observed in younger planetary nebula."

The nebula was brought to my attention by Aircrftr who found it at the edge of IC 1396 in one of his images http://www.cloudynights.com/topic/474123-what-do-you-make-of-this/ . It is only about 23 minutes of arc northwest of Mu Cephi, Herschel's Garnet Star which is just out of the field's lower left corner. I tried including it but it sent glare across the image beyond belief and had to be moved off the chip. The planetary is listed as a galaxy in the PGC extended catalog as PGC as #2584974 at magnitude 16.8. I don't know if it has ever been seen visually in an amateur scope.

The cropped larger view of the planetary shows a faint blue star in the center just left of the bright blue streak running from the southern edge up past the center. This is likely the central star causing the planetary to glow mostly in OIII light though it seems rather blue to me for just OIII emission which is more cyan in color.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME