20 light years long, and 2,400 light years away, this dark, dense nebula is part of a star-forming region (IC 1396). The Elephant’s Trunk itself is thought to contain several very young protostars. At the very top of the trunk you can see a tiny star that has ignited fusion and is now carving out a space within the dark cloud.
This image is made up of Sulfur, Hydrogen and Oxygen mapped to the Red, Green and Blue colour channels. The main column glows green from the Hydrogen gas that suffuses the entire complex, and is tinged yellow at the densest parts by the presence of Sulfur molecules. Toward the top of this picture you can see a little more blue, which is the presence of Oxygen in the wider molecular cloud. Hydrogen (green) is the dominant colour though. Given the vast scale of this region (the Elephant’s trunk itself being ~20 light years top-to-bottom) it’s a visual reminder that Hydrogen is the most common element in the Universe.
This image was created from 53 frames of RAW data — each a 900s exposure — in three narrowband filters. That makes this approximately 13 hours worth of data from the region! More technical details and labels of the objects in this image, can be found on Astrobin here.
The same image seen in RGB shows the Elephant’s Trunk is really a dark, dense cloud. Seen as a silhouette embedded within the glowing red of surrounding, energized hydrogen gas.