ithurtssobadly Posted November 16, 2023 Share Posted November 16, 2023 (edited) Hello. I just started astrophotography like 1 year ago and I still can't figure out how to counter this (zoom sometimes reset for my camera) I do smartphone astrophotography and i use Deepskycamera app to take pictures Everytime I observe, there's this black background around the circle fov which i really can't get rid of... Example is the image attached below This same black background ends up white after stacking all my light dark flat bias frames... Is there any way i can get rid of it? Thanks. Lights_0005_20231031_232140198000000.dng Edited November 16, 2023 by ithurtssobadly Link to comment Share on other sites More sharing options...
Cornelius Varley Posted November 16, 2023 Share Posted November 16, 2023 The black area around the central image is caused by the eyepiece. Please upload a jpeg or PNG version of the image so that it can be viewed in the browser. 1 Link to comment Share on other sites More sharing options...
Louis D Posted November 16, 2023 Share Posted November 16, 2023 If you are indeed performing afocal astrophotography and the black area outside the eyepiece's apparent field of view is bothering you, buy an eyepiece with an angular apparent field of view wider than the angular diagonal field of view of your camera. Link to comment Share on other sites More sharing options...
ithurtssobadly Posted November 17, 2023 Author Share Posted November 17, 2023 (edited) 14 hours ago, Louis D said: If you are indeed performing afocal astrophotography and the black area outside the eyepiece's apparent field of view is bothering you, buy an eyepiece with an angular apparent field of view wider than the angular diagonal field of view of your camera. My phone camera is around 120 degree fov maybe.. (using samsung s23 ultra) I can't find anything higher than that Also is there a way to fix this color noise in my image? Edited November 17, 2023 by ithurtssobadly my fov might be wrong Link to comment Share on other sites More sharing options...
ithurtssobadly Posted November 17, 2023 Author Share Posted November 17, 2023 13 hours ago, Cornelius Varley said: The black area around the central image is caused by the eyepiece. Please upload a jpeg or PNG version of the image so that it can be viewed in the browser. Ok, here Link to comment Share on other sites More sharing options...
Louis D Posted November 17, 2023 Share Posted November 17, 2023 Don't use an ultrawide angle camera lens with an eyepiece during afocal projection photography. As you've discovered, it results in a massive mismatch in fields of view if you do. Try using the wide angle and then the telephoto cameras to see if you get a better field of view match. For night photography, you'll definitely want to do pixel binning with those high resolution imagers behind those camera lenses. You could try taking ultrawide angle images of the night sky using that ultrawide camera. Just mount the camera to a tripod and take some images of different exposure lengths to see what you get. Link to comment Share on other sites More sharing options...
ithurtssobadly Posted November 17, 2023 Author Share Posted November 17, 2023 1 hour ago, Louis D said: Don't use an ultrawide angle camera lens with an eyepiece during afocal projection photography. As you've discovered, it results in a massive mismatch in fields of view if you do. Try using the wide angle and then the telephoto cameras to see if you get a better field of view match. For night photography, you'll definitely want to do pixel binning with those high resolution imagers behind those camera lenses. You could try taking ultrawide angle images of the night sky using that ultrawide camera. Just mount the camera to a tripod and take some images of different exposure lengths to see what you get. I see. Will try! Link to comment Share on other sites More sharing options...
ithurtssobadly Posted November 18, 2023 Author Share Posted November 18, 2023 23 hours ago, Louis D said: Don't use an ultrawide angle camera lens with an eyepiece during afocal projection photography. As you've discovered, it results in a massive mismatch in fields of view if you do. Try using the wide angle and then the telephoto cameras to see if you get a better field of view match. For night photography, you'll definitely want to do pixel binning with those high resolution imagers behind those camera lenses. You could try taking ultrawide angle images of the night sky using that ultrawide camera. Just mount the camera to a tripod and take some images of different exposure lengths to see what you get. but how do i do pixel binning Link to comment Share on other sites More sharing options...
Louis D Posted November 18, 2023 Share Posted November 18, 2023 I was reading up on your phone's cameras, and near as I can tell, simply choose lower resolutions. It will result in lower resolution images, but, for instance, 2x2 binning at 1/2 the linear resolution (1/4 total pixels) results in 4x as much light gathered per pixel. Give it a try at various resolution levels to see which produces the best compromise between resolution and image brightness. Lower resolution results in a shorter exposure time to get to the same image brightness (density) as at higher resolution. If your mount doesn't track, keeping exposures shorter will reduce image blurring as the Earth rotates under the sky. Link to comment Share on other sites More sharing options...
ithurtssobadly Posted November 18, 2023 Author Share Posted November 18, 2023 1 hour ago, Louis D said: I was reading up on your phone's cameras, and near as I can tell, simply choose lower resolutions. It will result in lower resolution images, but, for instance, 2x2 binning at 1/2 the linear resolution (1/4 total pixels) results in 4x as much light gathered per pixel. Give it a try at various resolution levels to see which produces the best compromise between resolution and image brightness. Lower resolution results in a shorter exposure time to get to the same image brightness (density) as at higher resolution. If your mount doesn't track, keeping exposures shorter will reduce image blurring as the Earth rotates under the sky. and should i also use an uhc filter which (possibly) can reduce light pollution? Link to comment Share on other sites More sharing options...
Louis D Posted November 19, 2023 Share Posted November 19, 2023 (edited) The UHC filter would probably help to reduce skyglow so you would get better contrast of nebula against the background skyglow. For star fields or open clusters, you probably want to avoid using a UHC filter because it throws off the star colors and would probably cause star bloat. You can always increase contrast on star fields in post processing by adjusting levels/curves. Edited November 19, 2023 by Louis D Link to comment Share on other sites More sharing options...
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