Stacking subs of different duration?

[catburglar]

Say I'm taking subs of 10s, 30s and 60s to capture an object with wide dynamic range - e.g. so I don't blow the trapezium in M42. Should I stack them in separate groups in DSS then align/combine the three layers in photoshop using layer masks and blends etc, or should I stack the whole lot in DSS and then duplicate the complete layer and mask etc....

 

Any thoughts?

[PeterCPC]

I would do the first option.

Peter

[angryowl]

Yes, stacking them separately is the way to go with different length exposures.

When I did my M31 I had 600s as my main exposures and some 30s ones to preserve detail in the core. Then I stacked and pre-processed them separately and finally combined in PI using the HDR Composition tool which resulted is an image with a high dynamic range showing both the faint detail in the core and detail in the galaxy arms.