Star mask question

[cmarcus]

Trying to perform this procedure : http://www.arciereceleste.it/tutorial-pixinsight/cat-tutorial-eng/75-narrowband-color-composition-eng

Which requires a star mask. My star mask is not hitting the big the stars. I have attached a screen shot where I have reversed the mask to show how the big stars are not covered, leaving in frame my star mask settings (as per the tutorial).

Any suggestions on how to improve the star mask would be very welcome.

TIA

[chris.bailey]

Try increasing the Scale parameter, I sometimes have to go up to9 to get all the stars in the mask but you should not increase it more than you need to.

[cmarcus]

Thank you for that, I shall try it. This is actually the first time I have ever tried to change any of the star mask settings, having up to now only used the default settings.

[lucchett]

Gerald's tutorial is spot on this.
You need to build two mask and add them together in pixelmath (small stars and big stars)
Andrea