A strange, ugly stain after HDRMultiscale transform?

[anteje]

Hi,
I am practicing PI with my photo of M42. After DBE, background neutralisation, color calibration and histogram transformation I tried HDRMultiscale transform.
But after HDRMultiscale transform I get strange stain - see screenshots. Any idea ?
Thanks

[pfile]

yes, this is because the core is completely overexposed and there's no real data there. the HDR transform gets confused.

make a range mask to protect the core during the HDR transformation and you'll be good.

better yet, get some shorter exposures and merge them in with HDRComposition before HDRMultiscaleTransform.

rob

[anteje]

Thanks, that's why I was afraid of.