BLACK DOG OBSERVATORY

CDD Images of Nebulae

Nebulae are clouds of dust and/or gas in space and they may be luminous or dark. Nebulae are the graveyards and birthplaces of the stars. Most nebulae are lit up by the stars within the cloud. Those that are not lit are seen as dark areas absent of stars and they look like 'dark patches' in the night sky surrounded by stars.

The main categories of nebulae are:

1. Emission Nebulae

   • They are the most colourful of nebulae and are lit up by the stars within the clouds of dust/gas.

2. Reflection Nebulae

   • These are lit up by reflected or scattered light from nearby stars. Reflection nebulae are often bluish because blue light is better reflected by dust particles in the nebula. A good example of this type of nebula and the bluish light is the Pleiades (The Seven Sisters; M45, NGC1432)

3. Diffuse Nebulae

   • They are irregularly shaped clouds of gas/dust. These nebulae contain elements of both emission nebula and reflection nebula. An example is the Eta Carinae Nebula (NGC3372)

4. Dark Nebulae

   • These are dense clouds of matter whose dust particles absorb light from stars beyond/behind it and give the appearance of starless patches against brighter surroundings.

5. Planetary Nebulae

   • They are the result of a dying star blowing off its outer layers which become visible as a thin shell of gas around the star. They have nothing to do with planets. About 1500 planetary nebulae have been discovered in the Milky Way. They are relatively short-lived at about 50,000 years. Some common examples of Planetary Nebulae are the Dumbell Nebula (M27), the Ring Nebula (M57) and the Helix Nebula (NGC7293).

Nebulae are my favourite deep space objects and I am still on the quest for the perfect shot.