Vertical band on image
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Dear All, I own a QSI683wsg with astrodon filters on a GSO RC10 Truss. Recently, imaging in bin2 I am getting a vertical bright band on the left of the image which obliges me to crop it to work on the image. This band is not present when imaging in bin1. I attach a highly?stretched raw image to show you the result. Any ideas about its origin and how to fix it? Should I just live with it and cropping or stop using bin 2 at all? Thanks for your help Nicola Sky Monsters - |
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Hi Paul, unfortunately calibrating the frame does not help, the band is still there. Nicola Il giorno mer 14 ago 2024 alle ore 23:46 Paul Homer via <phomer60=[email protected]> ha scritto:
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Nicola Sky Monsters - |
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Paul, I do have the dark frame with the same band, taken at the same temp and same binning. But still, it?doesn't get rid of that and I don't understand why Nicola Il giorno gio 15 ago 2024 alle ore 09:15 Paul Homer via <phomer60=[email protected]> ha scritto:
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Nicola Sky Monsters - |
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Hi Nicola.
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The bright bands on either side of the frame are normal for a KAF 8300 sensor in the QSI683, with the brightest band always on the left side, but they will calibrate out perfectly when you subtract a master bias frame from your master dark, master flat and the lights before calibrating the lights with the now bias-subtracted master dark and master flat.
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If you are not using a master bias frame this is possibly the reason that you can't remove that glow from the left side, if you are using a master bias as described above then possibly your calibration sequence is not correct.
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In the screen shot below are a master bias frame from a QSI683 on the left, 600 seconds master dark in the middle and a PixelMath subtraction (Master Dark - Master Bias) on the right. You can see that when the master bias is subtracted from the master dark that the bright bands on either side of the frame are removed.
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In theory, the bias component is included with the dark frame and should be removed from the light when the two are subtracted but my experience with this camera is that the edge glow is not linear and does not scale with the dark frame.
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Try creating a master bias at bin 2x2 and subtract the master bias from your master dark, master flat and the lights before going on to calibrate the bias subtracted lights with the bias subtracted dark and bias subtracted flat.
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The other thing I noticed in your image are the vertical column defects, these should have calibrated out of the frame when you subtracted the master dark but are still visible so is the image you posted a raw frame straight from the camera, in which case the edge glow at the left and right side are normal, or is the image dark subtracted, in which case the calibration process is not working or the calibration frames are incompatible.
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Check also that the camera cooling is working effectively, partial bright column defects like those in your image are a characteristic of a KAF8300 sensor that is not cooled.
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HTH.
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WIll.
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WILL B