Moon, 20cm SCT, F10, stacked stills.
Massive sunspots of Sept 4, 2017, stacked stills from video, solar filter, colored.
Imaging Performance Results
My relatively modest equipment consists of a 20cm F10 SCT equipped with a monochrome CMOS camera having a peak quantum efficiency of 81%. My sky's limited magnitude is only 3.5.
I typically run the camera at the following settings...
Deep Sky
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Typical Exposure – 1 to 10 seconds.
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Number of Exposures – 100 to 200.
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Typical Total Intergration Time – 5 to 10 minutes.
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Moderately high camera gain.
Sun/Moon/Planets
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Typical Exposure – 10 to 100 frames a second.
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Number of Exposures – 1,000 to 5,000.
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Maximum Total Intergration Time – 30 to 60 seconds.
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Low camera gain.
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Deep red filter.
My Typical Performance Results
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Laptop “Limiting Mag” is 15.5 (as viewed visually on the screen).
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Imaging with my 20cm SCT the limiting magnitude for stars is...
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1 second exposure – 15 mag
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5 seconds – 16 mag.
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30 seconds – 17 mag.
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15 minutes – 19 mag.
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With my 80mm F5 refractor I've recorded stars to magnitude 17.5 during a 6-minute exposure.
A full moon reduces these numbers by ~1.0 mag.
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Deep sky objects – generally can be imaged with some shape or detail to about 13 mag.
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Galaxy Imaging Results...
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Good results are obtained for galaxies down to mag 9.
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Acceptable to mag 11.
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Unacceptable to mag 13.
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Detectable down to mag 17.
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One should limit imaging galaxies to a surface brightness better than mag 22.0.
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Image resolution due to multi-image stacking...
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Down to 1.0 arc-seconds for deep-sky.
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Down to 0.5 arc-seconds for planets.
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