Best way to integrate two sets of Ha frames with different exposure lengths?

[rgbtxus]

I collected one set of Ha frames one night and another set of 15 min frames the next night.  I have flats for each night.  If I register and calibrate each set (registering them all against frame 1 of set 1) and then toss all the resulting frames into ImageIntegration, does it just figure out how to combine them appropriately?  Or, do I do something like ImageIntegration on set one, run LinearFit over each frame in set two using the integrated set one frame as the reference and then reintegrate all the frames (calibrates & registered from set one, calibrated, registered, fit from set 2)?
Richard

[mads0100]

HDRComposition tool.

http://pixinsight.com/forum/index.php?topic=4850.0

[rgbtxus]

I will try to figure that out (newbie here), but on the surface (again, newbie), this seems like an incorrect approach to my problem.  I increased exposure on the second night because it was clear I had plenty more headroom  If fact on night 2, the max value was .89 -- nothing was blown out.  The purpose of HDR, at a basic level, is to replace blown out areas with non blown out data from short exposures.  This is not my use case at all.

[rgbtxus]

Sorry, not sure if it matters, but I just noticed I forgot to specify that night one's images were 10min.  So i'm looking to combine some frames at 10min with others at 15min.

[pfile]

i think you are right; just select the best of your longer subs as the integration reference frame, and then integrate all the subs together. by default ImageIntegration is set up to weight images by SNR, so your longer subs will contribute more to the final stack than the shorter subs.

rob

[rgbtxus]

Thanks, that sounds perfect.  I probably would have just used a frame from first night for reference, so thanks for the save <G>