The Trifid Nebula (or M20 in the Messier Catalog, or NGC 6514), is an emission and reflection nebula in the constellation Sagittarius.

It got its name from it's three-lobed appearance, which also caused William Herschel to assign four different numbers to it, and he was also the one who gave it the name "Trifid".

It consists of a red emission nebula, surrounded by a larger blue reflection nebula, which is particularly visible in the northern part.

Its visual magnitude is somewhat uncertain; estimates lie between 6.8 and 9.0. Its distance from Earth is not know either, findings vary from 2,200 light years to 7,600 light years. Most seem to use 5,200.

The nebula is particularly interesting to students of the stellar life cycle, as it harbours an area of active star formation. However, many of the new stars trying to form will end up starving for gas as the surrounding material is blown away by the strong light and radiation from a hot new star.