Nebula come is several flavors. There are planetary nebula which are remnants from stellar explosive events that through clouds of hot gas from the surface of a star which glow and reflect light from nearby stars. Gaseous nebula can be emission or reflection or both types which either glow from internal heat around regions of stellar formation, usually reddish in color, or reflect light from nearby stars, usually bluish in color. There are also remains from supernova explosions involving whole star explosions. There are other things that are too odd to be classified as anything in particular but are basically big clouds of gas of some sort that can be seen with telescopes!

The Eagle Nebula, also M16, is located near Sagittarius in Serpens also contains an open star cluster of about 100 stars. This is an active star forming nebula with new stars near the center of the image. Taken at Henry Coe SP on October 2, 1999.

The Flame Nebula is part of a massive nebular complex in Orion. Taken October 2, 1999 at Henry Coe SP.

NEW! Color! The Helix Nebula is fairly large but dim. This is a result of a star blowing gas from its surface. Taken October 1, 2000 at CALSTAR. CMY composite of 10 minutes each color. Dark and bias corrected with no flat. ICX085AL based camera.

NEW! Color! The Horse head nebula is a very popular image! Taken at CALSTAR on September 30, 2000 around 3am Pacific. LCMY composite of 15 minute L and 5 minute each of CMY with ICX085AL based camera. Dark and bias corrected with no flat.

M27, the Dumbbell Nebula is another star surface eruption event. Taken September 22, 1999 at Mt. Diablo.

The Orion Nebula is another star forming cloud. This only show a small fraction of the total nebula. Taken on many occasions in late fall through winter. This object is very large and quite bright, this exposure was only four seconds.
 

The venerable Dumbell from White Mountain, Inyo National Forrest at Grandview campground, elevation 8500 ft. Composed of 8x1 minute exposures taken with Sony ICX085AL sensor. July 6, 2000 2:39am pacific.

The Omega Nebula from White Mountain, Inyo National Forrest at Grandview campground, elevation 8500 ft. Composed of 8x1 minute exposures taken with Sony ICX085AL sensor. July 6, 2000 1:23 am pacific.

The Trifid Nebula from White Mountain, Inyo National Forrest at Grandview campground, elevation 8500 ft. Composed of 8x1 minute exposures taken with Sony ICX085AL sensor. July 6, 2000 12:45 am pacific.

The Hercules Globular Cluster from White Mountain, Inyo National Forrest at Grandview campground, elevation 8500 ft. Composed of 3x75 second exposures taken with Sony ICX085AL sensor. July 6, 2000 2:10am pacific.