SteveBz Posted November 5, 2019 Share Posted November 5, 2019 Hi Guys, Does anyone use solar flats to flatten their solar images? I'm guessing now would be the time to make them. Do you have a complete workflow? Regards, Steve. Link to comment Share on other sites More sharing options...
Freddie Posted November 5, 2019 Share Posted November 5, 2019 (edited) Defocus whilst on a plain section (easy to find these days!!) of the sun surface , take a 5-10 sec AVI, stack in AS!3 to produce a master flat. Job done. You may be better off putting this in the imaging section! Edited November 5, 2019 by Freddie 1 Link to comment Share on other sites More sharing options...
SteveBz Posted November 5, 2019 Author Share Posted November 5, 2019 22 minutes ago, Freddie said: Defocus whilst on a plain section (easy to find these days!!) of the sun surface , take a 5-10 sec AVI, stack in AS!3 to produce a master flat. Job done. You may be better off putting this in the imaging section! I was thinking that you'd be better off averaging over a number of days to avoid the natural granularity of the sun becoming a factor. Is that not necessary? Regards Steve. Link to comment Share on other sites More sharing options...
SteveBz Posted November 5, 2019 Author Share Posted November 5, 2019 25 minutes ago, Freddie said: Defocus whilst on a plain section (easy to find these days!!) of the sun surface , take a 5-10 sec AVI, stack in AS!3 to produce a master flat. Job done. You may be better off putting this in the imaging section! Should I repost in imaging? Maybe one of the admins can move it. Link to comment Share on other sites More sharing options...
Freddie Posted November 5, 2019 Share Posted November 5, 2019 2 hours ago, SteveBz said: I was thinking that you'd be better off averaging over a number of days to avoid the natural granularity of the sun becoming a factor. Is that not necessary? Regards Steve. No, the defocus removes any detail. 1 Link to comment Share on other sites More sharing options...
SteveBz Posted November 5, 2019 Author Share Posted November 5, 2019 2 hours ago, Freddie said: No, the defocus removes any detail. OK, tx. I'll test it out. Link to comment Share on other sites More sharing options...
Pete Presland Posted November 5, 2019 Share Posted November 5, 2019 Using Firecapture allows the user to take a flat before the imaging run and apply it as the data is captured. The method is very simple, especially for the mosaics i do. I defocus, set the histogram to 50-70%, capture flat field. When you capture your data the flat is automatically applied. You have do a new flat whenever the imaging train is altered. Link to comment Share on other sites More sharing options...
tooth_dr Posted November 5, 2019 Share Posted November 5, 2019 I can fit the full disc on my 178MC, but cant get flats with it. Defocusing doesn't work, and a thin sandwich bag blocks out all the light. Any suggestions? Link to comment Share on other sites More sharing options...
SteveBz Posted November 6, 2019 Author Share Posted November 6, 2019 I was thinking of averaging over several days so that rotation of the sun removed any granulation. In the meantime you could download some from nasa/soho, after all, a sphere is a sphere is a sphere. But you might have to do something about aligning histograms - maybe. I haven't done any of this yet, but here's a flattened picture from soho. Additionally, I'd quite like to stretch the histogram from the top creating greater contrast and uncurl it by dividing by sin(theta) so that the edge artifacts don't look edge on. Good luck, Steve Link to comment Share on other sites More sharing options...
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