nSnRatio is the Signal to Noise Ratio of the
photometry measurement.CApphot:SNR
Returns the value of the Signal to Noise Ratio resulting from the photometry measurement. The value returned is the nSnRatio class member set by the Measure method.
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nSnRatio = CApphot:SNR() where |
nSnRatio is the Signal to Noise Ratio of the
photometry measurement.
The Measure method computes the signal to noise ratio of the object and saves it as the nSnRatio member of the class data structure. This method returns that value. The value of nSnRatio refers to the signal above background inside the object measuring aperture. It is calculated using the noise in the background sample as well as various instrumental parameters. In contrast, the SNRT method returns the signal to noise ratio based on theoretical parameters, using photon statistics instead of the noise actually measured in the background sample.