APOD 1.5: The Lagoon Nebula

 

This large lagoon nebula is home to many young star clusters and hot gas. This one spans 100 light years across and 500 light years away. It is so big, you can actually see it from earth without a telescope, towards the direction of the constellation Sagittarius. A bright knot of gas and dust in the nebula's center is known as the Hourglass Nebula.