Juan Pablo De la Cruz:
Jon Rista:
If you want to capture the star fully, then with very bright stars like that, the best option is to do multiple captures and HDR composition. Some stars are so bright they will saturate long before you can pick up any reasonable signal on fainter details, and its usually not worth completely sacrificing those details to keep the bright star(s).
With an HDR composition, you can blend across multiple integrations of shorter and shorter integrations to produce a higher dynamic range, supporting the entire range of the brighter star(s). This is usually how people capture good detail in the core of M42 (The Trapezium), while still capturing strong signal on the fainter details.
I have consistently used the same exposure settings for my deep-sky object (DSO) subs and am now interested in capturing finer details of bright stars within or surrounding the DSOs. I have a question regarding integration techniques. If I combine shorter subs, for example, 50 exposures of 20 seconds each, with longer subs, such as 20 exposures of 300 seconds each, would the shorter exposures contribute to enhancing the detail in the final image?"
You wouldn't want to stack them all together in a single integration (I know PI has some new scaling algorithms that are based on photometry, but even then, I still wouldn't stack them all into a single integration.)
What you would need to do is an HDR composition. For that, you would integrate your long, medium, short, etc. exposures into different integrations. Then you would combine them into a high dynamic range image by combining different signal ranges from each. PixInsight has an HDRComposition tool that can do this. I don't know if other popular astro processing tools do, but its worth checking. For any object where you feel you might have trouble with limited dynamic range in the hardware (and heck, even though ~14 stops is very good, its still far from enough to capture many brighter deep space objects well!) an HDR composition is the best way to expand the dynamic range to...well, any degree you want, really.
It is a process, though. You would integrate your 300 second subs into one integration, then integrate your 20 second subs into a second. You might even want to consider some middling length subs, maybe 150 seconds, to avoid funky transitions in the HDR composite. Once you have all of your individual integrations you would then HDR combine them. You may even be able to do this combination with Photoshop, which has long had 32-bit float HDR capabilities and HDR image composition tools.
