lsst.afw g1b7e58284d+7dcd958d67
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Functions | |
def | refraction (wavelength, elevation, observatory, weather=None) |
def | differentialRefraction (wavelength, wavelengthRef, elevation, observatory, weather=None) |
def | deltaN (wavelength, weather) |
def | densityFactorDry (weather) |
def | densityFactorWater (weather) |
def | humidityToPressure (weather) |
def | extractTemperature (weather, useKelvin=False) |
def | defaultWeather (altitude) |
Variables | |
float | deltaRefractScale = 1.0E8 |
def lsst.afw.coord._refraction.defaultWeather | ( | altitude | ) |
Set default local weather conditions if they are missing. Parameters ---------- weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation altitude : `astropy.units.Quantity` The altitude of the observatory, in meters. Returns ------- default : `lsst.afw.coord.Weather` Updated Weather class with any `nan` values replaced by defaults.
Definition at line 293 of file _refraction.py.
def lsst.afw.coord._refraction.deltaN | ( | wavelength, | |
weather | |||
) |
Calculate the differential refractive index of air. Parameters ---------- wavelength : `float` wavelength is in nanometers weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation Returns ------- deltaN : `float` The difference of the refractive index of air from 1., calculated as (n_air - 1)*10^8 Notes ----- The differential refractive index is the difference of the refractive index from 1., multiplied by 1E8 to simplify the notation and equations. Calculated as (n_air - 1)*10^8 This replicates equation 14 of [1]_ References ---------- .. [1] R. C. Stone, "An Accurate Method for Computing Atmospheric Refraction," Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.
Definition at line 123 of file _refraction.py.
def lsst.afw.coord._refraction.densityFactorDry | ( | weather | ) |
Calculate dry air pressure term to refractive index calculation. Parameters ---------- weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation Returns ------- densityFactor : `float` Returns the relative density of dry air at the given pressure and temperature. Notes ----- This replicates equation 15 of [1]_ References ---------- .. [1] R. C. Stone, "An Accurate Method for Computing Atmospheric Refraction," Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.
Definition at line 160 of file _refraction.py.
def lsst.afw.coord._refraction.densityFactorWater | ( | weather | ) |
Calculate water vapor pressure term to refractive index calculation. Parameters ---------- weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation Returns ------- densityFactor : `float` Returns the relative density of water vapor at the given pressure and temperature. Notes ----- This replicates equation 16 of [1]_ References ---------- .. [1] R. C. Stone, "An Accurate Method for Computing Atmospheric Refraction," Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.
Definition at line 195 of file _refraction.py.
def lsst.afw.coord._refraction.differentialRefraction | ( | wavelength, | |
wavelengthRef, | |||
elevation, | |||
observatory, | |||
weather = None |
|||
) |
Calculate the differential refraction between two wavelengths. Parameters ---------- wavelength : `float` wavelength is in nm (valid for 230.2 < wavelength < 2058.6) wavelengthRef : `float` Reference wavelength, typically the effective wavelength of a filter. 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 ------- differentialRefraction : `lsst.geom.Angle` The refraction at `wavelength` minus the refraction at `wavelengthRef`.
Definition at line 94 of file _refraction.py.
def lsst.afw.coord._refraction.extractTemperature | ( | weather, | |
useKelvin = False |
|||
) |
Thin wrapper to return the measured temperature from an observation. Parameters ---------- weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation useKelvin : bool, optional Set to True to return the temperature in Kelvin instead of Celsius This is needed because Astropy can't easily convert between Kelvin and Celsius. Returns ------- temperature : `astropy.units.Quantity` The temperature in Celsius, unless `useKelvin` is set.
Definition at line 269 of file _refraction.py.
def lsst.afw.coord._refraction.humidityToPressure | ( | weather | ) |
Convert humidity and temperature to water vapor pressure. Parameters ---------- weather : `lsst.afw.coord.Weather` Class containing the measured temperature, pressure, and humidity at the observatory during an observation Returns ------- pressure : `astropy.units.Quantity` The water vapor pressure in Pascals calculated from the given humidity and temperature. Notes ----- This replicates equations 18 & 20 of [1]_ References ---------- .. [1] R. C. Stone, "An Accurate Method for Computing Atmospheric Refraction," Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.
Definition at line 232 of file _refraction.py.
def lsst.afw.coord._refraction.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] R. C. Stone, "An Accurate Method for Computing Atmospheric Refraction," Publications of the Astronomical Society of the Pacific, vol. 108, p. 1051, 1996.
Definition at line 36 of file _refraction.py.
float lsst.afw.coord._refraction.deltaRefractScale = 1.0E8 |
Definition at line 33 of file _refraction.py.