31 May 2021: APP 1.083-beta2 has been released ! APP 1.083 stable will follow soon afterwards. It includes a completely new Star Reducer Tool, New File Saver Module, Improved Comet registration and much more, check the release notes here!
Processing Dark Nebula and dust
I’m working on NGC-1333 and using a RASA 8 (f/2) with an ASI294MC Pro and Optolong L-Pro filter. I’m having a hard time with trying to bring out the dark nebulosity and dust and was wondering if there was someone that has any advice or workflow that can be shared? My integration was 60x60 sec, 60x120 sec, and 40x180 sec with 60 darks for each time, 60 flats/dark flats and gain was 200. I’m in Bortle 5 skies. Should be doing something with HSL selective color on a particular color(s) or range? If anyone has had any success with dark nebula processing and can share some photos and tips using APP that would be awesome. Clear Skies!
Have you ever processed lights with different exposure times with darks with a single exposure time before? ASI cameras suffer quite a bit from amp glow and I have noticed that my ASI1600MM *needs* darks with exactly the same exposure time as the lights. That’s why I created a dark library with varying exposure times so I am prepared for an imaging session exactly the same as yours.
Dark nebulae are difficult, it's something that APP might have a better tool for in the future. I notice some have more success really getting the dark stuff out using Photoshop. I unfortunately don't have much experience with that though.
I have never tried using a single dark exposure time with lights at different times. I when working on this photo I did a multi session with dark frames that matched the times of each of my light image sessions. I have quite a good sized dark library 😊
What was also odd for me was that when I saved my preview after getting the image the way I wanted, the tiff and jpg files didn't look exactly like the preview. I had to adjust the image in Adobe Lightroom.
I too have Bortle 5 skies. I love APOD images showing smokey gray nebulae against dark deep space. I just don't think that Bortle 5 skies are dark enough. For me it shows itself as a region relatively devoid of stars but that's about it. One time I did have moderate success showing the nebula as a shade lighter than space but the required exposure was pretty extreme: 30 minutes luminance filter. In a single sub-frame I could see it but the downside was that deep space was 20,000 ADU. So what I figure is that the nebula is right at the level of sky brightness for Bortle 5 skies. You can increase your chances by imaging close to the zenith, an angle where the atmosphere is thinnest.
Oh yes, agreed, darker skies ofcourse. 🙂