GrismNRPGrismNRP - The rate of change of refractive index with wavelength

Description:
This attribute holds the rate of change of the refractive index of the grism material with respect to wavelength at the reference wavelength (given by attribute GrismWaveRGrismWaveR). The default value is 0.0 (the appropriate value for a pure grating disperser with no prism). The units of this attribute should be consistent with those of attributes GrismWaveR and GrismGGrismG.
Type:
Double precision.
Class Applicability:
GrismMapGrismMap
All GrismMaps have this attribute.