The ionized region is thought to be energized by the star HD 41997 (TYC1314-834-1 in the annotation). This is a special O-type star called a "runaway" since it has a significant space motion of greater than 40 km/s. The ionization region is about 1,000 to 1,800 light years distant.
So I learned a little about the amateur astronomer and pioneer astrophotographer Harold Lower. He is a hometown guy who lived in San Diego, California (my hometown). He and his son Charles were amateur astronomers, accomplished telescope makers and pioneering astrophotographers. Harold Lower published a pamphlet in 1939 describing an 8 inch Schmidt camera that he and his son had constructed. He used red filters and red sensitized film to capture nebulous structures such as his namesake, Sh2-261.
Image and details can be accessed at the link below (or by clicking on the Sh2-261 Region thumbnail image below); full size image can be accessed from the image webpage and has an image scale of 2.4 arcsec/pixel. The annotated image link is provided below, but that can also be accessed from the image webpage.
Annotated Image:
Sh2-261 Region Annotated
Scope: FSQ-106N at f/5
Camera: Atik 383L (Astronomik Gen 2 Ha, OIII , RGB Filters)
Location: DAA Observatory, Shelter Valley, CA
