The Cone Nebula and Christmas Tree Cluster, designated NGC 2264, consist of an open star cluster and an emission nebula located about 2,700 light years from Earth, seen from Earth in the winter constellation Monoceros.

In this image the brightest star is s-Monoceros, and it is located at the base of the Christmas Tree cluster. At magnitude 4.6, s-Monoceros is visible to the naked eye from locations on Earth with moderately dark skies.

The cone nebula is the oddly shaped emission nebula at the peak of the "christmas tree". It is part of a vast cloud of dust and gas energized by the nearby star s-Monoceros. The intense ultraviolet radiation from s-Monoceros causes hydrogen gas to ionize and glow, similar to the way that gas glows in a neon lamp. When there is a significant amount of dust mixed with the hydrogen, clumps of dust mixed with un-ionized hydrogen can shield the areas in their shadow from the energy of the nearby star, sometimes causing interesting shapes to appear. It is in these cooler, shaded regions where dust and un-ionized hydrogen condense over long periods of time to form new stars.

This image is a composite of 29 five minute exposures at ISO 800 made on 24-January-2009 from my back yard, with a Canon Digital Rebel XT (EOS 350D) attached to an 8" f/4.9 newtonian reflector.