Trumpler 16 (Tr 16) is a massive open cluster that is home to some of the most luminous stars in the Milky Way galaxy.

Its most luminous members are Eta Carinae and WR 25, with both having luminosities several million times that of the Sun, and there are three other extreme stars with O3 spectral classes.

However, Eta Carinae appears by far the brightest object, both because it is brighter in visual wavelengths and because it is embedded in nebulosity which exaggerates the luminosity.

Another cluster within Carina OB1, Collinder 228, is thought to be an extension of Trumpler 16 appearing visually separated only because of an intervening dust lane.

Because of the extreme luminosity of the stars formed, their stellar winds push away the clouds of dust, similar to the Pleiades.