differentialRefraction

lsst.afw.coord.differentialRefraction(wavelength, wavelengthRef, elevation, observatory, weather=None)

Calculate the differential refraction between two wavelengths.

Parameters:

wavelengthfloat

wavelength is in nm (valid for 230.2 < wavelength < 2058.6)

wavelengthReffloat

Reference wavelength, typically the effective wavelength of a filter.

elevationlsst.geom.Angle

Elevation of the observation, as an Angle.

observatorylsst.afw.coord.Observatory

Class containing the longitude, latitude, and altitude of the observatory.

weatherlsst.afw.coord.Weather, optional

Class containing the measured temperature, pressure, and humidity at the observatory during an observation If omitted, typical conditions for the observatory’s elevation will be calculated.

Returns:

differentialRefractionlsst.geom.Angle

The refraction at wavelength minus the refraction at wavelengthRef.