Colour rendering of Orion Nebula area

This is a composite of three 1-min exposures of the Orion Nebula through narrow band filters centred on the 2.166 micron Br-gamma atomic hydrogen line (here reproduced in blue colour), the 1.257 micron [FeII] line (green) and the 2.12 micron 1-0 S(1) molecular hydrogen line (red). The colour coding reflects the ionisation state of the gas. Br-gamma traces hydrogen gas that is ionised by the well known Trapezium and other hot, young, stars in the region ; the [FeII] emission is emitted by high velocity fragments ejected during the birth of new stars in the OMC1 molecular cloud. The hollow filaments seen in molecular hydrogen result from shock heating of the molecular gas in the wake of the outflowing matter. In this image, the scale is 0.29 arcsec/pixel ; the field is 5x5 arcmin with North at the top and East to the left ; the seeing was around 0.5 arcsec.