Clive Posted May 9, 2021 Share Posted May 9, 2021 1 hour ago, RonC said: I do save the images to file as I usually adjust them in DSS before saving. Do you save the with the adjustments applied? (I was under the impression that isn't necessarily a good idea) Link to comment Share on other sites More sharing options...
+RonC Posted May 9, 2021 Author Share Posted May 9, 2021 I do Clive, have always done that as the 90 and 120s subs from the 183c are usually quite dark. Just to lighten them enough for processing. Link to comment Share on other sites More sharing options...
Bottletopburly Posted May 9, 2021 Share Posted May 9, 2021 I think it’s best not to save adjustments, you only need the stacked image as your processing will sort everything else . Link to comment Share on other sites More sharing options...
Clive Posted May 9, 2021 Share Posted May 9, 2021 I've always thought that that the adjustments in DSS apply a non-linear stretch. If so, that makes subsequent processing much more difficult where a process relies on ideally linear data (eg background removal). Your processing software should be able to do a linear stretch so it is 'brighter'. Link to comment Share on other sites More sharing options...
+RonC Posted May 9, 2021 Author Share Posted May 9, 2021 I'll take that under advisement 😀 Link to comment Share on other sites More sharing options...
Bottletopburly Posted May 9, 2021 Share Posted May 9, 2021 You can turn stretching off in Dss ron see image ,Ivo from startools has a dss settings for using in startools but they will work for any processing suite https://www.startools.org/links--tutorials/starting-with-a-good-dataset/deep-sky-stacker-settings Link to comment Share on other sites More sharing options...
+RonC Posted May 9, 2021 Author Share Posted May 9, 2021 Not far off what I use but I've made notes on it! Bottletopburly 1 Link to comment Share on other sites More sharing options...
+RonC Posted May 13, 2021 Author Share Posted May 13, 2021 Well I got an hour of clearish sky last night, not brilliant but clear enough! Picked M3 at 60' or so and did 5 x 120s at 1x1 and 5 x 120s at 2x2 binnng. No dew shield, no filters but guided. Still seems to be a gradient on the 2x2 and not the 1x1 binning?? The 1x1 image was darker than the 2x2 image although I have slightly stretched both. This is the 1x1 binning. This is the 2x2 binning. Link to comment Share on other sites More sharing options...
Clive Posted May 13, 2021 Share Posted May 13, 2021 Excuse my ignorance but is the binning done 'in camera' or in the post-processing software? I thought binning an OSC 'in camera' resulted in a monochrome image but that obviously may not be the case here! Link to comment Share on other sites More sharing options...
+RonC Posted May 13, 2021 Author Share Posted May 13, 2021 In camera Clive, 1x1 - 4x4.. Link to comment Share on other sites More sharing options...
Clive Posted May 13, 2021 Share Posted May 13, 2021 17 minutes ago, RonC said: In camera Clive, 1x1 - 4x4.. Is it possible for you to bin the 1x1 images in software to 2x2? I would hope that the result should similar to 2x2 binning in-camera but possibly without the gradient? As to how in-camera binning could produced a gradient, who knows, but maybe someone does? (Software sometimes does some very strange and unexpected things!) Link to comment Share on other sites More sharing options...
Clive Posted May 13, 2021 Share Posted May 13, 2021 Thinking about it, 2x2 binning is effectively increasing the camera sensitivity by x4 and reducing the noise by x2 (ish) so any light pollution will become more visible? +RonC 1 Link to comment Share on other sites More sharing options...
+RonC Posted May 13, 2021 Author Share Posted May 13, 2021 (edited) If I binned 1x1 Clive I would just process it in that form. The only reason I bin 2x2 is the file size, 2x2 9Mb 1x1 40Mb! I have contacted Ian at Altair Astro for advice.. Ron Edited May 13, 2021 by RonC Link to comment Share on other sites More sharing options...
+Ibbo Posted May 13, 2021 Share Posted May 13, 2021 As I posted last weeek can we see the cali frames It would be useful to see the raw image ,the flat and the dark and bias if used as the raw fits files uploaded to dropbox so we can then download Are the cali frames being taken in the shut up obs or the camera covered ? zip them up if you can Link to comment Share on other sites More sharing options...
+RonC Posted May 13, 2021 Author Share Posted May 13, 2021 Hi Steve, my Dropbox is full!! Darks taken same night with the cam covered. Library of Flats and Dark flats used (I may update them this weekend!) Link to comment Share on other sites More sharing options...
+RonC Posted May 14, 2021 Author Share Posted May 14, 2021 I think with Steve's help I've sorted the gradient problem!! The Flats I used were over exposed so after taking a number of new Flats at different exposures, I think it's now sorted!! M51 - new Flats. Bottletopburly 1 Link to comment Share on other sites More sharing options...
Clive Posted May 14, 2021 Share Posted May 14, 2021 Pleased you've found the answer! Link to comment Share on other sites More sharing options...
+Ibbo Posted May 14, 2021 Share Posted May 14, 2021 Hopefully Ron. Slight fly in the oniment I can see some dust bunnies round the edge -could be things have changed since you took the data. Link to comment Share on other sites More sharing options...
+RonC Posted May 14, 2021 Author Share Posted May 14, 2021 Yes Steve it's an old image!! Link to comment Share on other sites More sharing options...
+Ibbo Posted May 14, 2021 Share Posted May 14, 2021 Ah that may explain it then. Link to comment Share on other sites More sharing options...
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