Besides the luminous bright nebulae of various types, consisting of light
emitting gas or illuminated dust masses, there are dark nebulae which can be
seen because they obscure, or absorb, the light coming from stars or bright
nebulae behind them. Therefore, dark Nebulae are sometimes called Absorption
Nebulae.
A famous example is the Horsehead Nebula.
The earliest documented and probably most conspicuous dark nebula is the
Coalsack in the southern constellation
Crux.
Early known dark nebula: Coalsack
Planetary Nebulae
Messier's catalog does not contain any dark nebula.
Diffuse Nebulae
![[Nebula]](http://www.messier.seds.org/Jco/nebula.ico.jpg)
![[SEDS]](http://www.messier.seds.org/Jco/seds1.jpg)
![[MAA]](http://www.messier.seds.org/Jco/maa.jpg)
![[Home]](http://www.messier.seds.org/Jco/messier.jpg)
![[Indexes]](http://www.messier.seds.org/Jco/sheet.ico.jpg)
Supernova Remnants