Processing

Once I began processing the data it was possible to draw out some details. The signal was still very weak though, and I ran into many problems.

First, noise. Normally I use Topaz DeNoise AI, but I’d heard good things about the recently released NoiseXTerminator plug-in for PixInsight. I gave it a go and wow, it’s impressive. See below for a before / after slider comparison. NoiseXTerminator will be my go-to noise reduction method from now on.

The next problem was controlling star sizes. There are countless pin-pricks of light in the image, and quite a few larger stars too. I find that Generalised Hyperbolic Stretch does an excellent job of stretching to non-linear while controlling stars, so used that to good effect. I then used StarNet2 to remove the stars, and did a bit of work to reduce their number before adding them back in.

The third big problem was with colour. To get any detail I was mangling the data quite hard, and as a result was producing lurid colours. I wrestled with this for a while, and in the end did a fair amount of desaturation. This helped, but unfortunately removed some nice blue nebulosity. Oh well.

In all, this was a really tough target to image and process. I can see that dark skies would really help to produce a much better end result, but hey, at least it’s possible for city astrophotographers to glimpse the Shark too.