Sh2-78 aka CTSS3

CTSS-33 was originally cataloged by Stewart Sharpless as an HII region, and is listed as Sh2-78 in his catalog. In 1990, an Italian team used a technique comparing the Palomar Observatory Sky Survey plate used by Sharpless with a new infrared survey plate, also from Palomar, and determined that Sh2-78 is actually a planetary nebula - hence the alternative name CTSS-3 (Cappellaro Turatto Salvadori Sabbadin 3). It is a large, late stage planetary nebula located in Aquila.
CTSS-3 is reported to be at a distance of about 2200 light years and to have a diameter of about 12 arcmin. However, in this image it is evident that besides its intense ”boxy” inner structure it also has a weaker, previously unknown outer structure, extending at least 20 arcmin, giving it an elongated, three-dimensional or moving appearance.

My thanks to Sven Eklund for providing his excellent data on this target.
Data acquisition and pre-processing by Sven Eklund
Post-processing by Peter Goodhew
Captured using Sven's remote telescope in Spain.
More information at https://www.imagingdeepspace.com/sh2-78.html