This in an incredibly faint object – EGB 6 – discovered by Ellis, Grayson, and Bond in 1984 in a visual search through prints from the Palomar Sky Survey. Here is a link to their original paper.

EGB 6 is an old and hence large planetary nebula with extremely low surface brightness. The image is a bicolor composite of more than 50 Ha and OIII exposures of 1800 sec each – more than 25 hours of data. Nonetheless, heavy stretching and masked histogram transformations were necessary to extract some signal, even with the excellent conditions at Deep Sky West. I added a tad of RGB stars added to it. Maybe I will try again from scratch to see if there is more in the data…