This video covers using HDRMultiScale Transform (MDRMT) to Open up blocked highlights in your image.

Most of what we image is extraordinarily faint - but sometime you will have very bright portions where you lose detail in the highlights. This is common with the bright core of galaxies, brighter portions of some nebulae, and some areas of bright emission Ha regions.

HDRMT can redistribute the code values at the top of your tonescale by using a Multiscale method.