Emission nebula in Perseus. If I shot the entire length and flipped it left to right it really would look like CA!
Emission nebula in Cassiopeia
Planetary nebula in Aquarius
NGC 6888 is an emission nebula in Cygnus, about 5000 ly distant. This is CFHT palette in narrowband light. About 5 hours or Ha and 3 each of OIII, SII and luminance.
Taken at Two Goats Observatory (my driveway). Five hours of Ha, two and two thirds hours each of SII and OIII plus two hours of luminance data. This is a false color image so called because it maps Ha to red, OIII to green and SII to blue even though SII is an even deeper red than Ha. Narrowband (NB) filters enhance contrast of emission objects by accepting only a narrow range of wavelengths around the emission lines of hydrogen (H-a, 656 nm), oxygen (OIII, 501 nm), sulfur (SII, 672nm)
M27, a planetary nebula in Vulpecula in CFH telescope narrowband palette.
M16, the Eagle Nebula in Serpens. Over thirty hours of narrowband data (Ha, OIII and SII) mapped to the Canada-France-Hawaii Telescope palette. Where the Hubble palette maps Ha to green, SII to red and OIII to blue, the CFHT palette is Ha-OIII-SII as RGB.
The Horsehead Nebula and Flame Nebula in Orion.
The Orion Nebula is a diffuse nebula situated south of Orion's Belt in the constellation of Orion. Part of the Orion Molecular Cloud Complex, you can see part of the Running Man Nebula on the left.
The western veil nebula, a supernova remnant in Cygnus
The Owl Nebula, a planetary nebula in Ursa Major
The Ring Nebula, a planetary nebula in Lyra
The Dumbbell Nebula, a planetary nebula in Vulpecula
The Trifid Nebula, an H II region in Sagittarius.
The Lagoon Nebula
The Crab Nebula, a supernova remnant in Taurus