DETAILS
Exposure: 17×1200″ @ ISO 800
Telescope: Skywatcher Newton 8″ f5 with Baader MPCC
Filter: Baader H-alpha 7nm 2″
Mount: Skywatcher EQ6 Pro
Camera: Modded Canon 350D in cooler box
Date: 13th and 14th July 2009
Location: Cabrera de Mar (suburban site near Barcelona)
Comments: I’m particularly happy with this image. Narrow band with a DSLR camera is complicated.

The Elephant’s Trunk nebula is a concentration of interstellar gas and dust in the star cluster IC 1396 and ionized gas region located in the constellation Cepheus about 2400 light-years away from the Earth. The piece of the nebula shown in the image is the dense globule IC 1396A; it is commonly called the Elephant Trunk nebula because of its appearance at visible wavelengths, where it is a dark patch with a bright, sinuous rim. The bright rim is the surface of the dense cloud that is being illuminated and ionized by a very bright, massive star that is just to the west of IC 1396A. The entire IC 1396 region is ionized by the massive star, except for dense globules that can protect themselves from the star’s harsh ultraviolet rays.
The Elephant Trunk nebula is now thought to be site of star formation, containing several very young (less than 100,000 years) stars that were discovered in infrared images in 2003. Two older stars are present in a small, circular cavity in the head of the globule. Winds from these young stars may have emptied the cavity.
The combined action of the light from the 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.