Synphot Data User's Guide
2.6 Quantum Yield Correction (WFC3)
The qyc keyword is used to apply a wavelength-dependent quantum yield correction.
At short wavelengths, the UVIS detector has a finite chance of producing two elections for one incoming photon. By default, synphot reports the raw count rate in electrons (if the dn keyword is not specified) or data numbers (if the dn keyword is specified), but the appropriate count rate for signal-to-noise calculations should be in electrons with a correction for this quantum yield effect.
For signal-to-noise calculations, users should specify the qyc keyword but not specify the
We expect to implement this functionality for other instruments in the future.
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