The Hii Regions M42 and M43

Abstract

The photographic investigation of the Orion Nebula has a history of almost 100 years: the first photograph of the object was obtained by Anslie Common in 1883. Since then numerous photographs have been obtained by both professional and amateur astronomers all over the world. A compilation of the most recent photographs taken in the light of various emission lines and the continuum are presented in Table 2.1.I. Some relevant details concerning the ionization state of the most important elements from which the emission lines originate are presented in Table 2.1.II. The relative and absolute strengths of the most important lines are presented in Table 2.1.IIIa and 2.1.IIIb, respectively.