did you know that there are different types of nebula??
1)planetary--nebulae that form from the gaseous shells that are ejected from low-mass  giant  stars when they transform into white dwarves.
2)protoplanetary
3)The expanding shell of gas form a supernova remnant, a special type of diffuse nebula

Notable named nebulae

• Eta Carinae Nebula
• Orion Nebula
• Hourglass Nebula
• Horsehead Nebula
• Rosette Nebula
• Ring Nebula
• Crab Nebula
• Barnard's Loop
• Red Square Nebula
• Tarantula Nebula
• Boomerang Nebula

these photos are from http://en.wikipedia.org/wiki/Nebulae#Specific_types_of_nebulae

Isn't this interesting!!!