Optical spectrum of the bipolar nebula

Optical spectrum of the bipolar nebula of a young, massive star in M 17, obtained with EFOSC2 at the ESO 3.6 m telescope and with EMMI at the ESO 3.5 m NTT, both located on La Silla, Chile. A number of identified emission lines, like Hα and the Ca II triplet 849.8, 854.2 and 866.2 nm, are denoted.