refraction

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

Calculate overall refraction under atmospheric and observing conditions.

Parameters:

wavelength : float

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

elevation : lsst.geom.Angle

Elevation of the observation, as an Angle.

observatory : lsst.afw.coord.Observatory

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

weather : lsst.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:

refraction : lsst.geom.Angle

The angular refraction for light of the given wavelength, under the given observing conditions.

Notes

The calculation is taken from [1].

References

[1]	(1, 2) R. C. Stone, “An Accurate Method for Computing Atmospheric Refraction,” Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.