TMB92_SBig2_4K_IC434_CHproc_18Feb06Mar11-APBlend.jpg
TMB92_SBig2_4K_IC434_CHproc_18Feb06Mar11-APBlend.jpg
TMB92_SBig2_4K_IC434_CHproc_18Feb06Mar11-APBlend.jpg
The popular Horse Head Nebula. Much of the image is Emission Nebula data, narrow color band emitted from hot glowing gases.
But the Horse Head and general are below it is a dark Nebula. Thick gases and dust particles that block out any light passing through that area. In effect the Horse Head is a projected shadow.