Thread: Trifid & Lagoon
View Single Post
Old 14-06-2018, 11:05 AM
sil's Avatar
sil (Steve)
Not even a speck of dust

sil is offline
Join Date: Jun 2012
Location: Canberra
Posts: 1,279
both more sub and longer can help, but I think your bottleneck here is processing rather than data. your image looks nice and clean and I feel the nebolsity can be brought out further from the darkness. I dont know if DSS has fine enough controls for that, but i suspect it does for the patient. Longer subs will naturally give you brighter nebulosity while more subs will give you better signal to noise ratio to allow more agressive stretching. The nebulosity is there already though. Look at your individual subs though and check the lagoon isn't overexposing. looking at your jpg there is much more lagoon already there in the image waiting for you to tease it out.

This is where you start learning to use masks to allow you to stretch only parts of the data not the whole image. Aligning and stacking alone doesnt give you that great image unless you are lucky. Adjusting levels wont either. You need to adjust various parts of the histogram where the signal is lurking and just stretch that bit forward. Then repeat for another area and slowly you build it all up. Curves may be a good place to start experimenting too.

The DSS default settings are good to get you started but not always an ideal place to start. When you have time reprocess and carefully check EVERY option available, read what it does and decide what to use. Always choose the best slowest option if in doubt, it gives you a cleaner more accuratelty aligned final image with less artifacts introduced, so when you start stretching you have better signal and less noise to work with. Ignore if it takes overnight to run , it often does in astrophotography, there is no one click solution really. DSS is the Fischer Price of AP programs, yet it does have strong features that plenty of people master to get magnificent pictures from it. But they all take effort from the user to make it happen.

Even the commercial packages need the user to work at it to get good images. You may want to consider AstroPixelProcessor. Its not far off a one click package but has tons of power when you need it and the default settings work superbly. I think its a good affordable step up from DSS if you're not yet keen to go to something like PixInsight (my package of choice, but there are other high end quality packages others here prefer). APP's defaults and autostretch give a damn good image ready to save as jpeg, tell you what if you want to email your 10 subs for this image to me at sjbolton at gmail dot com I'll chuck them through AstroPixelProcessor and post the result. I'm betting the nebulae will be brighter by default and wider. And it'll give you an idea of what your data has and if its worth considering buying some better software than DSS.

Or it could come out worse or the same. But I doubt it. I'll just see what the defaults do on their own.

One other point i think you may be a tad out of focus (a constant struggle for us all).
Reply With Quote