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Published byVanessa Bailey Modified over 9 years ago
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Simon Dawes Artemis 285
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Kit
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Assembly
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The Completed Camera
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Problem 1 Thermal readout noise Solution: 1.New Peltier 2.More thermal paste on peltier (although Dark subtraction was quite effective)
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Problem 2 Dust donuts! Solution: Flat fielding Light box (although they can sometimes be removed with clever processing)
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Problem 3 & 4 Gradient from top left to bottom right Solution: Turn off Amp during exposure (Latest software always selects this for long exposures) Weird patterns! – Dew on CCD Solution: Seal the cold frame, desiccant was trying to dry the whole Earth! CCD was dripping wet
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Problem 5 (will they ever stop) Another weird pattern! - Frost Solution: Thermal paste sealing CCD window, to warm the window slightly
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Flat field light box
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Raw 15s Frame, note top-bottom gradient and dust donuts
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Stacked, dark subtracted, cube route scaled, de-convolved
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Notice dust donuts (poor flat field) and sky gradient going from top left to bottom right
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Median rank operator removes small scale structure, leaving the sky gradient, donuts and Globular
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19,000 is added to every pixel in original image
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One Image is subtracted from the other, removing gradient and donuts
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Background is smoothed to remove some noise
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Any pixel value less than 21,000 ADU is set to 17,000ADU
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Black and white levels are adjusted
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