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lsst.afw g712618294e+4813a5392e
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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.