Above is the image of Lagoon Nebula also known as M8. A nebula is an interstellar cloud of gas and dust and a star forming region.The picture also includes foreground and background stars which lie along same line of sight.In the picture,as we can see,red emission or H-alpha emission from atomic hydrogen dominates this nebula’s visible light but narrow band filters(Narrowband filters capture only a very small part of the spectrum) were used to record the image data and map the hydrogen emission to green hues, with emission from sulfur atoms in red and oxygen in blue.This nebula spans about 30 light years and is at distance of about 5000 light years towards the constellation Sagittarius.

Source – NASA APOD

Credits and Copyrights – Russel Croman