snr_derived

specutils.analysis.snr_derived(spectrum, region=None)[source]

This function computes the signal to noise ratio DER_SNR following the definition set forth by the Spectral Container Working Group of ST-ECF, MAST and CADC.

Parameters
spectrumSpectrum1D

The spectrum object overwhich the equivalent width will be calculated.

region: `~specutils.utils.SpectralRegion`

Region within the spectrum to calculate the SNR.

Returns
snrQuantity or list (based on region input)

Signal to noise ratio of the spectrum or within the regions

Notes

The DER_SNR algorithm is an unbiased estimator describing the spectrum as a whole as long as the noise is uncorrelated in wavelength bins spaced two pixels apart, the noise is Normal distributed, for large wavelength regions, the signal over the scale of 5 or more pixels can be approximated by a straight line.

Code and some docs copied from http://www.stecf.org/software/ASTROsoft/DER_SNR/der_snr.py