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Dave,
Ive read your thread with some interest
Taking on such a tiny dim planetary nebula under an almost full moon in bortle 7 with a massive light bucket is a “HUGE” challenge, however I admire the fact you decided to go for it and did salvage an image.
I’m only a few km away from you ( when I’m in Sydney) and my yard borders on Bortle 8 as I have Las Vegas neighbours either side of me most nights
My observations
Firstly the L Extreme does not act as a bonifide light pollution filter like I thought it did a while back. Yes it helps but you still need to mitigate the LP and moon glare noise floor with calibration frames , dithering and processing.
Secondly, 2.5 hrs seems a bit shy for optimum SNR on such a tiny dim object with that 294MC. More like + 4 hrs would yield improved SNR under those sky conditions that evening ( obviously its not always possible )
I capture all my images with my 2600MC bin 1x1 and let Startools work it’s magic with binning for optimum SNR and resolution ( 90% of time the default Bin 50% works really well as I’m oversampled at around 0.70 arc sec per pixel )
Under your sky conditions that night good calibration frames are a must. I don’t really know what works with the 294MC ( my 2600MC uses Flats and Bias which works well under all conditions)
Startools requires clean linear data from the stacker ( no intervention after stacking )
Big crops in Startools before Wipe through to the final noise reduction is a big no no . By massive cropping before processing in Startools your effectively taking away usable data which has a negative effect on the softwares ability
Perform your initial stretch using AutoDev, Bin 50% then use Crop to trim the edges for stacking artifacts , then Wipe and on to your final stretch in Autodev
Leave your massive crop for the final saved image.
As far as stretching is concerned some folk use Filmdev which is not the recommended way as Filmdev applies a stretch across the whole image at a uniform way whereas Autodev stretches the image to apply dynamic range where its needed to highlight structures and other details
The only 2 tools I use in Autodev which yields good results is ROI ( I use the mouse a draw a ROI ) and the “Ignore fine detail” slider. The rest of the settings I leave as default
Another advantage of using AutoDev is that it’s almost impossible to black clip your data which is sometimes too easy to do with other software programs
Anyway enough for now , I could blabber on forever
Hope the above offers some practical advice
Again well done on your capture of NGC3132 I’m sure a re process in Startools would yield some improvements
Clear Skies
Martin
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