MICADO grating efficiencies

[oczoske]

Needs to be a new effect - sort of a transmission per spectral trace, needs to be applied to the FOV before mapping to the XiLamImage. There is an effect MetisLMSEfficiency (branch oc/spectraces_lms), but that computes the efficiency for the wavelength setting and then applies it to all traces. For MICADO, the efficiencies can be read from a file but must be applied for each trace separately. A possible solution would be to build the grating efficiency into the SpectralTraceList effect, However, as long as the FOVs are uniquely identified with a trace, a standalone effect should work and would be more in line with the basic idea of Effects.