The most observed emission nebula in the Northern Hemisphere is the famed Orion Nebula (M42), lying some 1,300 light-years away. Visible to the naked eye as a misty spot of stars, this cloud of gas is forming an infant star cluster, the four brightest of which are called the Trapezium. This wide-field view shows the Orion Nebula at left with bluish reflection nebulae around it, the brightest of which is NGC 1973–5–7, at right.