dust.py 文件源码

def from_fluxd(cls, wave_or_freq, fluxd, aper, eph, Tscale=1.1,
                   T=None):
        """Initialize from flux density.

        Assumes the small angle approximation.

        Parameters
        ----------
        wave_or_freq : `~astropy.units.Quantity`
          Wavelengths or frequencies of the observation.

        fluxd : `~astropy.units.Quantity`
          Flux density per unit wavelength or frequency.

        aper : `~astropy.units.Quantity`, `~Aperture`
          Aperture of the observation as a circular radius (length
          or angular units), or as an sbpy `Aperture` class.

        eph : dictionary-like or `~Ephem`
          Ephemerides of the comet, describing heliocentric and
          geocentric distances as `~astropy.units.Quantity` via
          keywords `rh` and `delta`.  `rh` is not required when `aper`
          is in units of length.

        Tscale : float, optional
          Blackbody temperature scale factor.  Ignored if `T` is
          provided.

        T : `~astropy.units.Quantity`, optional
          Use this temperature for the Planck function.


        Example
        -------
        >>> from sbpy.activity import Efrho
        >>> import astropy.units as u
        >>> wave = 15.8 * u.um
        >>> fluxd = 6.52 * u.mJy
        >>> aper =  11.1 * u.arcsec
        >>> eph = {'rh': 4.42 * u.au, 'delta': 4.01 * u.au}
        >>> efrho = Efrho.from_fluxd(wave, fluxd, aper, eph=eph)
        >>> efrho.cm                              # doctest: +FLOAT_CMP
        120.00836963059808

        """

        fluxd1cm = Efrho(1 * u.cm).fluxd(wave_or_freq, aper, eph=eph,
                                         Tscale=Tscale, T=T)
        fluxd1cm = fluxd1cm.to(fluxd.unit, u.spectral_density(wave_or_freq))
        return Efrho((fluxd / fluxd1cm).decompose() * u.cm)