IC5146 is also known as the Cocoon Nebula and lies in the constellation of Cygnus.  It is approximately 4000 light years from the earth and spans a distance of almost 15 light years.  The central star is the primary illuminating source of ultraviolet radiation that excites the surrounding molecular cloud of gas causing it to glow in the red part of the spectrum.  Gas and dust surrounding the beautiful red emission nebula is visible as a reflection nebula and shines in the blue part of the spectrum.  The Cocoon Nebula is a stellar nursery with most of the stars forming within approximately the last million years.  The central star is estimated to have formed only one hundred thousand years ago.  Dr. Robert Gendler published a very informative and detailed article describing the Cocoon Nebula and may be viewed here.

¹http://en.wikipedia.org/wiki/IC_5146
²http://www.robgendlerastropics.com/Cocoontext.html