I checked and my notes read "At 278x in 10-inch was a small diffuse glow that was more evident than I expected it to be." No filter was used. And as you'll see in the image below, Hakann, it's not a true "ring" nebula.
M33 Far Northern Nebula.jpg
I checked and my notes read "At 278x in 10-inch was a small diffuse glow that was more evident than I expected it to be." No filter was used. And as you'll see in the image below, Hakann, it's not a true "ring" nebula.
M33 Far Northern Nebula.jpg
Contributing Editor for Sky & Telescope
8x56, 10x50, 12x60, 15x70 binoculars
130mm, 150mm, 10-inch SCT, 16-inch ES Dob