Eta Carinae nebula. Enhanced optical image of the heart of the Eta Carinae nebula (NGC 3372). This cloud of gas and dust surrounds the wildly erratic variable star Eta Carinae in the constellation Carina. The nebula is lit up by ionisation of its hydrogen gas by radiation from hot, massive stars embedded in it. Dark regions of interstellar dust cross this region, absorbing the light of the stars and nebula. Eta Carinae itself is unusual, having fluctuated between magnitude -0.8 and 8 in the last hundred years. This image was produced by a CCD (charge-coupled device) camera, which stores images electronically rather than on film.