StarTools

So here is my first attempt playing with startools, I have defiently overdone it and didnt take the time with masking on some stars! To fair I was just clicking around and seeing what diffrent tools did!
http://176.126.241.47/orion-final.png

I have uploaded the orginal stack here, if anyone would be so kind to try my data to see there results/process: http://176.126.241.47/orion.zip
The data is nothing special, 15 images of 30 second exposures.

I have to say that's a really good go for a first try!

It's really quite nice deep data you got there, but the only thing that lets it down is the lack of flats. They're not optional!
What are the acquisition details? M42's core typically comes out greenish, which I wasn't able to accomplish that well with this data. I wonder if some sort of filter was used?

Given the wicked gradients/vignetting, I went for a slightly more conservative processing that still shows a pretty standard workflow you should be able to use for most images even once you start taking flats. There are ways to workaround data that has flaws, but at the end of the day it's just better to learn how to produce better data than working around bad data (which will never look 100% right).
Processed as follows;

File loaded [/home/irwjager/Downloads/orion.fts].
---
--- Auto Develop
To see what we got. We can see the gradient/vignetting, sever oversampling and some small tracking issues. Very low noise though at first glance, which is great!
--- Bin
To convert oversampling into even better signal-to-noise.
Parameter [Scale] set to [(scale/noise reduction 35.38%)/(798.89%)/(+3.00 bits)]
--- Crop
Cropping stacking artifacts and worst of the vignetting.
Parameter [X1] set to [386 pixels]
Parameter [Y1] set to [261 pixels]
Parameter [X2] set to [1856 pixels (-272)]
Parameter [Y2] set to [1374 pixels (-46)]
--- Wipe
Used Vignetting preset, and created mask that masked out the central part of M42 so that it is not mistaken for gradient.
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [Precision] set to [512 x 512 pixels]
Parameter [Dark Anomaly Filter] set to [4 pixels]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [85 %]
--- Auto Develop
Final stretch. Click & dragged Region Of Interest over M42's core.
Parameter [Ignore Fine Detail <] set to [5.2 pixels] to make AutoDev ignore fine noise.
Parameter [Outside ROI Influence] set to [6 %]
--- Deconvolution
Clicked AutoMask for automatic mask generation (since the current mask with M42's core masked out is not a suitable star mask)
Parameter [Image Type] set to [Deep Space]
Parameter [Radius] set to [2.7 pixels]
Parameter [Iterations] set to [6]
Some nice detail enhancement,
--- Wavelet Sharpen
Using same mask we made during Decon.
Parameter [Amount] set to [315 %]
Parameter [Small Detail Bias] set to [97 %]
--- Contrast
Default parameters.
--- Color
Usually comes up with a reasonable color balance by itself (as is the case here).
Preferably do this towards the end of your processing (like here).
Parameter [Dark Saturation] set to [7.00]
Parameter [Green Bias Reduce] set to [1.12]
Pulled back on the green a little as the MaxRGB view showed dominant green in areas that I would not expect it.It could be the gradients that are throwing off the expected green in the core...
--- Wavelet De-Noise
Final noise reduction by switching Tracking off.
Parameter [Grain Size] set to [9.2 pixels]
Parameter [Smoothness] set to [78 %]

That's it!

Hope this helps...

Just to confirm no filter was used, was taken using a 8" SCT with a 6.3 focal reducer and a Nikon DSLR.
Thank you for taking the time to have a look, your guide was really helpful. Today I tried taking some flats and re-stacked the data using them.
Below is the new image I have got following your guide, and seem to have got the green in the core you mentioned: Possibly green needs to be reduced a little more, but you have defiantly helped give me a nice workflow process, so thank you again