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Alex,
Workflow for creation of good Star Mask and using Shrink , Dim Small and Isolate ( Superstructure) to reduce Star field in Startools v1.7 or v1.8
Star Mask
NB: As stars are made up of many pixels , undersampled data , heavy binning or heavy cropping will reduce resolution and therefore reduce the number of pixels that make up a Star. This will have a knock on and negative affect in creating a good Star Mask as Stars will end up blocky when you zoom in making it impossible to ensure a good round Star Mask covering the whole stellar profile of the Star.
If your image scale is oversampled ( below 1 arc sec per pixel ) which is ideal then recommend Cropping edges only and maximum Bin 50%
Press Mask at top
Then press Auto
Set Filter Sensitivity to 1
All other settings default
Press Do
Basic Star Mask appears
Note 1: Any stars not sampled or green can be masked by setting Brush Mode below to “Flood Fill Lighter Pixels “ and then click on Star core white pixels to start mask and click on white pixels just outside green mask to expand mask.
Alternatively you can use Brush Mode “Lasso” and draw mask around Star
Note 2 : Any small or tiny stars not fully masked , just use the “Grow” button at the top. One click at a time. If you grow too big use the reverse button “Shrink”
Important !!!
Ensure the whole Star is masked out green , slightly overlapped the better
Shrink Module
To be used after main processing just before Colour module and final noise reduction
Make sure you have a good Star Mask set with all stars sampled or green
Select Shrink
Shrink may ask you to set a Star Mask , select “Keep Mask as is “
Ensure Mode setting is set to “Tighten”
Adjust iterations from default 10 up to 20 and use before and after button to inspect Star size and brightness reduction
All other settings leave as default
NB: If Stars have large than normal halos use Uni glow Strength and Uni glow Kernel sliders below to reduce halos
Once satisfied with Star field press Keep
Superstructure Module ( Dim Small and Isolate presets )
Can be used after Shrink and either before colour or after colour module and before noise reduction
Make sure you have a good Star Mask set with all stars sampled or green. Then press “Invert” at top so that stars now are “not sampled” white and background is green or sampled
Press Keep
Now select Superstructure Module
Superstructure may ask you to set a Mask, select “Keep Mask as is”
Then press “Dim Small” preset at top.
The only slider to adjust will be “Strength” Default is 100%
NB: Don’t increase past 100% only reduce down to 90, 80 , 70 , 60 to 50%
Once satisfied with the Star field reduction press Keep
Further Star reduction ( Optional ) is “Isolate”
Select Superstructure module again
Keep Star Mask as is
Select “Isolate” preset at top
Reduce “Strength” from default 100% down to at least 50% or 40% as this feature is quite aggressive
Once satisfied with Star field reduction, press Keep
Now select Star Mask at top again and press “Clear” then “Keep”
Star reduction is now completed !!
Your now ready to finalise your processing using Colour and then final Noise Reduction
Hope the above helps
Cheers
Martin
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