Graham Darke Posted April 10, 2021 Share Posted April 10, 2021 Was out imaging from a nice dark site last night SQM reading of 21.41. This was a quick capture while I waited for M13 to rise. 10x180s and 5x300s stacked in DSS and processed in StarTools. TEC140 and ASI071MC-Pro Camera at 0 degrees C. 13 Link to comment Share on other sites More sharing options...
kirkster501 Posted April 10, 2021 Share Posted April 10, 2021 Very nice. Nice colours and framing. I think you have slightly over-clipped the black point - to reduce noise or to eliminate a gradient? A bit of noise is OK. Link to comment Share on other sites More sharing options...
Graham Darke Posted April 10, 2021 Author Share Posted April 10, 2021 Not sure how black point adjustment works in StarTools. It always seems to produce a black background. Link to comment Share on other sites More sharing options...
Clarkey Posted April 10, 2021 Share Posted April 10, 2021 2 hours ago, Graham Darke said: Not sure how black point adjustment works in StarTools. It always seems to produce a black background. One of problems I have with ST is that I never get a black background! I seem to get lots of noise instead.... Despite changing settings and watching Ivo's videos I never get clean results. Lots of detail, but much noisier than any other processing. Nice image though. I wish I could get this detail in such a short time. 1 Link to comment Share on other sites More sharing options...
Avocette Posted April 10, 2021 Share Posted April 10, 2021 (edited) 3 hours ago, kirkster501 said: Very nice. Nice colours and framing. I think you have slightly over-clipped the black point - to reduce noise or to eliminate a gradient? A bit of noise is OK. I just downloaded the image and at least in GIMP the histogram doesn’t show any black level clipping from my perspective (well the 0 brightness pixel count is 191 out of a total of 3724225). Edited April 10, 2021 by Avocette Link to comment Share on other sites More sharing options...
CCD Imager Posted April 12, 2021 Share Posted April 12, 2021 I like this image, a lovely cluster of galaxies with interesting detail and well captured. The background does appear quite dark and I had a look in Photoshop. Using the colour sampling tool, levels are about 5, so although not strictly clipped, an optimum value should be around 20-30 giving a more natural appearance, after all nobody's skies are truely black.. I havent used Star tools, but it might be worth speaking to the author Adrian 1 Link to comment Share on other sites More sharing options...
Graham Darke Posted April 12, 2021 Author Share Posted April 12, 2021 I had another go at this one. The background is still very dark but I always find that with StarTools. This one is a bit noisier but I think I like the colour of this one better. I think I deliberately throttled the development (stretching) on the first one to prevent a satellite trail from showing up. I've restacked the subs in DSS using Kappa-Sigma Clipping and its done a better job of removing it. Link to comment Share on other sites More sharing options...
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