The Carina Nebula is 8.500 lightyears away in the constellation Carina. It was discovered by Nicolas-Louis de Lacaille in 1752 from his observatory at the Cape of Good Hope. This giant molecular cloud  is one of the most active star forming regions in our galaxy with over 60.000 young stars and a total mass of over 1 Million M☉
High energy ultraviolet photons from the young stars strip the surrounding hydrogen atoms of their electron. When these free electrons recombine with protons they cascade down the energy levels. As electrons fall from the third to the second lowest energy level, they emit a photon with a wavelength of 656 nanometer, the hydrogen alpha band, visible as deep-red light. 
In the central part of the Carina Nebula is the open cluster Trumpler 16 with the Keyhole Nebula and the star system Eta Carinae, the most massiv star known in our galaxy. Trumpler 16 with over 80 young, hot and massive stars produces the bulk of the energy for the Carina Nebula.