The Elephant Trunk Nebula is a concentration of interstellar gas and dust within the much larger ionized gas region IC 1396, located in the constellation Cepheus, about 2,400 light years away.
The piece of the nebula shown in this image is the dark, dense globule IC 1396A; it is commonly called the Elephant Trunk nebula because of its appearance at visible light wavelengths, where there is a dark patch with a bright, sinuous rim. The bright rim is the surface of a dense cloud that is being illuminated and ionized by a very bright, massive star that is just to the east of IC 1396A (ie, just off the top of the image).
The entire IC 1396 region is ionized by this massive star, except for the dense globules that can protect themselves from the star's harsh ultraviolet rays.
The Elephant Trunk Nebula is now thought to be a site of star formation, containing several very young stars that were discovered in infrared images in 2003. Two older (but still young, a couple of million years) stars are present in the small, circular cavity in the head of the globule.
The combined action of the light from this massive star ionizing and compressing the rim of the cloud, and the wind from the young stars shifting gas from the center outward, lead to very high compression in the Elephant Trunk Nebula. This pressure has triggered the current generation of protostars.
40x180sec Lights each in Ha, Sii and Oii filters, with Darks, Flats and Bias. Sii is mapped to Red, Ha to Green and Oiii to Blue, with the channels then adjusted to give the classic Hubble Palette.