I use DSS for Deep Sky because it's easy it seems the time to move to PI. > "Options" - Background Options - Calibration Method set to "Rational", RGB Channels Background Calibration set to "Minimum" > click on "RGB Channels Background Calibration" I found back a recipe (source forgotten) for DSS which seems to give much better results:ĭSS > Settings Menu > Stacking Settings > Light tab >Ĭlick where it says "RGB Channels Background Calibration" drop-down menu It looks like the problem indeed is in the processing. Yea Jim, I clearly have to learn more about colour CMOS. But as mentioned, this is only a presentation effect on the screen. Or you can stretch the image where it dies a colour balance and shows a normal colour image. This shows the image with the colour Bias. It can be where all red, blue and green are stretched equally. Next we colour calibrate the integrated image into a normal colour image.ĭepending on what processing software you use, you can change the way the image is "on screen only" stretched. Next comes aligning and integrating all the images into a single colour image. It's not always green, mine are sometimes blue or brown, depending on the light pollution filter I have used. This usually leaves the images with a green background. So our process normally is to calibrate the images (with darks, flats, etc.). This is so we can process the image before it is debayered. However, for astrophotography (and other forms of photography) we want the images completely unprocessed. They then colour balance the 4 pixels into a normal colour image. Normally DSLR cameras auromatically process the image so that this Bayer pattern is dealt with. There are 2 green filters because the human eye is more sensitive to green. It is because the sensors have what's called a Bayer pattern, where there is a grid in front of each group of pixels that contain a matrix of two green, one red and one blue filter. Or I should say that all colour camara sensors produce a green image. Just in case you don't already know this.Īll colour cameras produce a green image. It has no affect on the raw image as saved to disk. But remember this only changes APT's Preview display. For example, I have my Red scale = 1.1 and Blue = 1.5. You can change the bias applied to the red and blue colour channels, by using "APT Settings > CCD tab > de-bayer Red/Blue Channel Scaling Factor" setting. However, it's default bias for each colour may not always produce an unbiased colour image. APT does attempt to deal with this bias for it's Preview window display. onedrive) and post a link, so I can have a look.Īs capture software is only interested in capturing images, and not processing them, they often show a colour biased image. Are you saying your processing can't deal with the level of colour bias? If so, what processing software are you using? Can you upload an image you are having trouble with to a file share somewhere (e.g. You just process it out as part of your normal processing. About 50% of the book is devoted to describing "tours" of the sky, with physical and observational descriptions, at-the-eyepiece drawings, and photographs.A green bias is quite normal. The prospective city-based observer is told why to observe from home (there are hundreds of spectacular objects to be seen from the average urban site), how to observe the city sky (telescopes, accessories, and moderns techniques), and what to observe. This book covers the "why," "how," and "what" of astronomy under light-polluted skies. This book describes the many objects that can be seen in a bright urban sky, and shows the city or suburban astronomer how to observe object after object, season after season. Due to this light pollution, they are under the impression that deep sky objects - nebulae, galaxies, star clusters- are either invisible or not worth viewing from home. Many of them, however, live in urban and highly developed suburban areas that are heavily light polluted. Most amateur astronomers yearn to observe more frequently.
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