Drax Spacex Posted November 1, 2022 Share Posted November 1, 2022 https://ibb.co/ZchWXYv What is this dark spot in LASCO c3? It has persisted in the same pixel locations since 2022-10-13. It looks like a inverse polarity snapshot of a prior planetary passage, dark instead of bright. The image brightness in that sector increased on 2022-10-13 which revealed this dark spot (perhaps an automatic background level adjustment relating to the Venus passage?). I wonder if it is revealing a sensor/pixel/screen burn-in problem for that area, or if it is a background brightness algorithm issue that can be manually reset or will resolve itself automatically? Link to comment Share on other sites More sharing options...
Vancanneyt Sander Posted November 1, 2022 Share Posted November 1, 2022 36 minuten geleden, Drax Spacex zei: I wonder if it is revealing a sensor/pixel/screen burn-in problem for that area Seems like it, it’s the same Venus that’s burned into it. Haven’t noticed it in the past decade. CCD is pretty old so maybe it’s starts wearing off. 2 Link to comment Share on other sites More sharing options...
Sam Warfel Posted November 1, 2022 Share Posted November 1, 2022 3 hours ago, Vancanneyt Sander said: Haven’t noticed it in the past decade. Flexing 😂 Link to comment Share on other sites More sharing options...
Solution Jesterface23 Posted November 1, 2022 Solution Share Posted November 1, 2022 (edited) It almost looks like a calibration filter. Looking a bit more into it, it's the C3 filter used when processing the images. https://drive.google.com/file/d/1JY15nWhC8MFK9x6OcUm_y6cGppwYeG8D/view?usp=share_link Edited November 1, 2022 by Jesterface23 1 Link to comment Share on other sites More sharing options...
Sam Warfel Posted November 2, 2022 Share Posted November 2, 2022 6 hours ago, Jesterface23 said: It almost looks like a calibration filter. Looking a bit more into it, it's the C3 filter used when processing the images. https://drive.google.com/file/d/1JY15nWhC8MFK9x6OcUm_y6cGppwYeG8D/view?usp=share_link I don’t see a spot in that image that would correlate to the one Drax pointed out, am I missing something? Link to comment Share on other sites More sharing options...
Jesterface23 Posted November 2, 2022 Share Posted November 2, 2022 (edited) 33 minutes ago, Orneno said: I don’t see a spot in that image that would correlate to the one Drax pointed out, am I missing something? On the right side the horizontal line can be made out in the filter. The circle is sort of hidden in one of the bright rings near right-center, but can be made out somewhat. And it is bright in the filter, not dark. Here is a raw level 0.5 SOHO LASCO C3 image to get an idea of what the correction does. Noting also that both images are normalized to see things better. You can hardly see bright CMEs in the raw imagery. https://drive.google.com/file/d/1jrdFVzkjaFW_fvvKHzMxHzU5ZuKKIPUK/view?usp=share_link Edited November 2, 2022 by Jesterface23 1 Link to comment Share on other sites More sharing options...
Sam Warfel Posted November 2, 2022 Share Posted November 2, 2022 8 hours ago, Jesterface23 said: On the right side the horizontal line can be made out in the filter. The circle is sort of hidden in one of the bright rings near right-center, but can be made out somewhat. And it is bright in the filter, not dark. Here is a raw level 0.5 SOHO LASCO C3 image to get an idea of what the correction does. Noting also that both images are normalized to see things better. You can hardly see bright CMEs in the raw imagery. https://drive.google.com/file/d/1jrdFVzkjaFW_fvvKHzMxHzU5ZuKKIPUK/view?usp=share_link Very interesting, thanks. I had no idea the images were processed like that Link to comment Share on other sites More sharing options...
Drax Spacex Posted November 2, 2022 Author Share Posted November 2, 2022 (edited) 16 hours ago, Jesterface23 said: It almost looks like a calibration filter. Looking a bit more into it, it's the C3 filter used when processing the images. https://drive.google.com/file/d/1JY15nWhC8MFK9x6OcUm_y6cGppwYeG8D/view?usp=share_link Yes, I see this same spot and lines in the C3 filter image. This discrete artifact may have been tagged as CCD fixed pattern noise, stray light or other sampled background noise. A new filter image would probably fix this (whether this is manually or automatically generated I do not know). An overview of the image calibration steps can be found in paragraph 12.3: https://lasco-www.nrl.navy.mil/index.php?p=content/handbook/hndbk_12 Good news is this is something that can be addressed in the Earth-based Image processing pipeline. Hopefully the raw images transmitted from the LASCO instrument itself are still OK (except for a few dead pixels here and there!). Edited November 2, 2022 by Drax Spacex noise sources 1 1 Link to comment Share on other sites More sharing options...
Solarflaretracker200 Posted November 2, 2022 Share Posted November 2, 2022 16 hours ago, Jesterface23 said: On the right side the horizontal line can be made out in the filter. The circle is sort of hidden in one of the bright rings near right-center, but can be made out somewhat. And it is bright in the filter, not dark. Here is a raw level 0.5 SOHO LASCO C3 image to get an idea of what the correction does. Noting also that both images are normalized to see things better. You can hardly see bright CMEs in the raw imagery. https://drive.google.com/file/d/1jrdFVzkjaFW_fvvKHzMxHzU5ZuKKIPUK/view?usp=share_link That's actually interesting. Link to comment Share on other sites More sharing options...
Drax Spacex Posted November 8, 2022 Author Share Posted November 8, 2022 This appears to have been fixed in LASCO c3 imagery as of 2022-11-08 04:54. 1 Link to comment Share on other sites More sharing options...
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