December 2013: the hidden secrets of M42

If there’s a visited target in the sky, that’s for sure M42.

The bright Orion Nebula is an easy target for any type of equipment and expertise. But this object hides inside its core some secrets which are a challenge to uncover. How can this be?


The intense core of the nebula is so bright that images are overexposed. To avoid this, one must take short exposures subs. But at the same time, short exposures cannot get the detail out of the fainter part of the object.

The technique I used on this baby was based on the High Dynamic Range method. With it, one take several short exposures of the object, so that it doesn’t get overexposed. With a tool like HDRComposition in PinxInsight, this set is combined with the regular, long exposed frames, to yield an image which has a huge dynamic range to work with.

With my configuration, M42 is simply too big for the FOV, so I used a mosaic of two parts. I also used the H-alfa filter, to get the most out of it. Finally, a touch of deconvolution made the details clearer.

As you see in the picture, the core part of the nebula perfectly seen. Even the famous trapezium has been uncovered by this technique.

  Go to this object description and this image technical detail.