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| Joint Astronomy Centre |
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Typical limit magnitude for point sources
Signal to Noise Ratio CalculationsThe theory behind the signal to noise behaviour of aperture
photometry from IR imaging cameras can be found
here.
The situation can be simplified under the following assumptions:
into two cases, depending on whether the object contributes significantly more or less light into the object aperture than the sky background. In addition, you should note that signal to noise ratio is inversely proportional to the square root of your object apperture area. Faint ObjectsWhen the object is much fainter than the sky, the achieved signal to noise ratio is proportional to the square root of integration time, proportional to the flux of the object and inversely proportional to the square root of the sky flux. Bright ObjectsWhen the object is much brighter than the sky, the achieved signal to noise ratio is proportional to the square root of integration time and proportional to the square root of the flux from the object. |
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