The Orion Nebula (M42)

 The individual images of the Orion Nebula where obtained with WFI at the ESO/MPG 2.2m telescope on the night of Dec.10-11, 2001. Several images were obtained in the following filters: U (363.690 nm; 15 images for a total exposure time of 1.25 hour); B (456.252 nm; 14 images; total exp.: 21 min); Oxygen [OIII] (502.393 nm; 15 images; total exp.: 32 min); Halpha (658.827 nm; 15 images; total exp.: 32 min); Sulphur [SII] (676.340 nm; 10 images; total exp.: 30 min). ESO Press Photo eso0421 is a false-colour composite of all of the images obtained in B, Halpha, [OIII], and [SII] where each waveband was associated to a given colour: B to blue, [OIII] to green; Halpha to orange, and [SII] to red. The field of view covers 34 x 33 arcmin2. North is up and East is to the left. The images were first processed by Massimo Robberto (STSci) then further combined by Hännes Heyer and Henri Boffin (ESO).