def binned_pixelrange(self, waverange, **kwargs):
"""Calculate the number of pixels within the given wavelength
range and `binset`.
Parameters
----------
waverange : tuple of float or `~astropy.units.quantity.Quantity`
Lower and upper limits of the desired wavelength range.
If not a Quantity, assumed to be in Angstrom.
kwargs : dict
Keywords accepted by :func:`synphot.binning.pixel_range`.
Returns
-------
npix : number
Number of pixels.
Raises
------
synphot.exceptions.UndefinedBinset
Undefined `binset`.
"""
if self.binset is None:
raise synexceptions.UndefinedBinset(
'No binset specified for this passband.')
x = units.validate_quantity(
waverange, self._internal_wave_unit, equivalencies=u.spectral())
return binning.pixel_range(self.binset.value, x.value, **kwargs)
def _process_graphtable(graphtable):
"""Load and cache graphtable. Get primary area."""
global _GRAPHDICT
# Use default graph table if not given
if graphtable is None:
gtname = conf.graphtable
else:
gtname = graphtable
# Load and cache graphtable, if not in cache
if gtname in _GRAPHDICT:
gt = _GRAPHDICT[gtname]
else:
gt = GraphTable(gtname)
_GRAPHDICT[gtname] = gt
# Set telescope collecting area
if gt.primary_area is None:
area = conf.area
else:
area = gt.primary_area
primary_area = units.validate_quantity(area, units.AREA)
return gt, gtname, primary_area
def _process_graphtable(graphtable):
"""Load and cache graphtable. Get primary area."""
global _GRAPHDICT
# Use default graph table if not given
if graphtable is None:
gtname = conf.graphtable
else:
gtname = graphtable
# Load and cache graphtable, if not in cache
if gtname in _GRAPHDICT:
gt = _GRAPHDICT[gtname]
else:
gt = GraphTable(gtname)
_GRAPHDICT[gtname] = gt
# Set telescope collecting area
if gt.primary_area is None:
area = conf.area
else:
area = gt.primary_area
primary_area = units.validate_quantity(area, units.AREA)
return gt, gtname, primary_area
def binned_pixelrange(self, waverange, **kwargs):
"""Calculate the number of pixels within the given wavelength
range and `binset`.
Parameters
----------
waverange : tuple of float or `~astropy.units.quantity.Quantity`
Lower and upper limits of the desired wavelength range.
If not a Quantity, assumed to be in Angstrom.
kwargs : dict
Keywords accepted by :func:`synphot.binning.pixel_range`.
Returns
-------
npix : number
Number of pixels.
Raises
------
synphot.exceptions.UndefinedBinset
Undefined `binset`.
"""
if self.binset is None:
raise synexceptions.UndefinedBinset(
'No binset specified for this passband.')
x = units.validate_quantity(
waverange, self._internal_wave_unit, equivalencies=u.spectral())
return binning.pixel_range(self.binset.value, x.value, **kwargs)
def thermback(self, area=None, thermtable=None):
"""Calculate thermal background count rate for
``self.obsmode``.
Calculation uses
:func:`~stsynphot.observationmode.ObservationMode.thermal_spectrum`
to extract thermal component source spectrum in
PHOTLAM per square arcsec. Then this spectrum is
integrated and multiplied by detector pixel scale
and telescope collecting area to produce a count rate
in count/s/pix. This unit is non-standard but used widely
by STScI Exposure Time Calculator.
.. note::
Similar to IRAF SYNPHOT THERMBACK.
Parameters
----------
area : float, `~astropy.units.quantity.Quantity`, or `None`
Area that flux covers.
If not a Quantity, assumed to be in :math:`cm^{2}`.
If `None`, use `area`.
thermtable : str or `None`
Thermal component table filename.
If `None`, uses ``stsynphot.config.conf.thermtable``.
Returns
-------
bg : `~astropy.units.quantity.Quantity`
Thermal background count rate.
Raises
------
synphot.exceptions.SynphotError
Calculation failed.
"""
if self.obsmode.pixscale is None:
raise synexceptions.SynphotError(
'Undefined pixel scale for {0}.'.format(self.obsmode))
if area is None:
area = self.area
area = units.validate_quantity(area, units.AREA)
sp = self.obsmode.thermal_spectrum(thermtable=thermtable)
bg = sp.integrate() * self.obsmode.pixscale ** 2 * area
return bg.value * (u.count / u.s / u.pix)
def thermback(self, area=None, thermtable=None):
"""Calculate thermal background count rate for
``self.obsmode``.
Calculation uses
:func:`~stsynphot.observationmode.ObservationMode.thermal_spectrum`
to extract thermal component source spectrum in
PHOTLAM per square arcsec. Then this spectrum is
integrated and multiplied by detector pixel scale
and telescope collecting area to produce a count rate
in count/s/pix. This unit is non-standard but used widely
by STScI Exposure Time Calculator.
.. note::
Similar to IRAF SYNPHOT THERMBACK.
Parameters
----------
area : float, `~astropy.units.quantity.Quantity`, or `None`
Area that flux covers.
If not a Quantity, assumed to be in :math:`cm^{2}`.
If `None`, use `area`.
thermtable : str or `None`
Thermal component table filename.
If `None`, uses ``stsynphot.config.conf.thermtable``.
Returns
-------
bg : `~astropy.units.quantity.Quantity`
Thermal background count rate.
Raises
------
synphot.exceptions.SynphotError
Calculation failed.
"""
if self.obsmode.pixscale is None:
raise synexceptions.SynphotError(
'Undefined pixel scale for {0}.'.format(self.obsmode))
if area is None:
area = self.area
area = units.validate_quantity(area, units.AREA)
sp = self.obsmode.thermal_spectrum(thermtable=thermtable)
bg = sp.integrate() * self.obsmode.pixscale ** 2 * area
return bg.value * (u.count / u.s / u.pix)
def binned_waverange(self, cenwave, npix, **kwargs):
"""Calculate the wavelength range covered by the given number
of pixels centered on the given central wavelengths of `binset`.
Parameters
----------
cenwave : float or `~astropy.units.quantity.Quantity`
Desired central wavelength.
If not a Quantity, assumed to be in Angstrom.
npix : int
Desired number of pixels, centered on ``cenwave``.
kwargs : dict
Keywords accepted by :func:`synphot.binning.wave_range`.
Returns
-------
waverange : `~astropy.units.quantity.Quantity`
Lower and upper limits of the wavelength range,
in the unit of ``cenwave``.
Raises
------
synphot.exceptions.UndefinedBinset
Undefined `binset`.
"""
if self.binset is None:
raise synexceptions.UndefinedBinset(
'No binset specified for this passband.')
# Calculation is done in the unit of cenwave.
if not isinstance(cenwave, u.Quantity):
cenwave = cenwave * self._internal_wave_unit
bin_wave = units.validate_quantity(self.binset,
cenwave.unit,
equivalencies=u.spectral())
return binning.wave_range(bin_wave.value, cenwave.value, npix, **
kwargs) * cenwave.unit
def binned_waverange(self, cenwave, npix, **kwargs):
"""Calculate the wavelength range covered by the given number
of pixels centered on the given central wavelengths of `binset`.
Parameters
----------
cenwave : float or `~astropy.units.quantity.Quantity`
Desired central wavelength.
If not a Quantity, assumed to be in Angstrom.
npix : int
Desired number of pixels, centered on ``cenwave``.
kwargs : dict
Keywords accepted by :func:`synphot.binning.wave_range`.
Returns
-------
waverange : `~astropy.units.quantity.Quantity`
Lower and upper limits of the wavelength range,
in the unit of ``cenwave``.
Raises
------
synphot.exceptions.UndefinedBinset
Undefined `binset`.
"""
if self.binset is None:
raise synexceptions.UndefinedBinset(
'No binset specified for this passband.')
# Calculation is done in the unit of cenwave.
if not isinstance(cenwave, u.Quantity):
cenwave = cenwave * self._internal_wave_unit
bin_wave = units.validate_quantity(
self.binset, cenwave.unit, equivalencies=u.spectral())
return binning.wave_range(
bin_wave.value, cenwave.value, npix, **kwargs) * cenwave.unit
def grid_to_spec(gridname, t_eff, metallicity, log_g):
"""Extract spectrum from given catalog grid parameters.
Interpolate if necessary.
Grid parameters are only read once and then cached.
Until the cache is cleared explicitly using
:func:`reset_cache`, cached values are used.
Parameters
----------
gridname : {'ck04models', 'k93models', 'phoenix'}
Model to use:
* ``ck04models`` - Castelli & Kurucz (2004)
* ``k93models`` - Kurucz (1993)
* ``phoenix`` - Allard et al. (2009)
t_eff : str, float or `astropy.units.quantity.Quantity`
Effective temperature of model.
If not Quantity, assumed to be in Kelvin.
If string (from parser), convert to Quantity.
metallicity : str or float
Metallicity of model.
If string (from parser), convert to float.
log_g : str or float
Log surface gravity for model.
If string (from parser), convert to float.
Returns
-------
sp : `synphot.spectrum.SourceSpectrum`
Empirical source spectrum.
Raises
------
stsynphot.exceptions.ParameterOutOfBounds
Grid parameter out of bounds.
synphot.exceptions.SynphotError
Invalid inputs.
"""
if gridname == 'ck04models':
catdir = 'crgridck04$'
elif gridname == 'k93models':
catdir = 'crgridk93$'
elif gridname == 'phoenix':
catdir = 'crgridphoenix$'
else:
raise synexceptions.SynphotError(
'{0} is not a supported catalog grid.'.format(gridname))
metallicity = _par_from_parser(metallicity)
if isinstance(metallicity, u.Quantity):
raise synexceptions.SynphotError(
'Quantity is not supported for metallicity.')
log_g = _par_from_parser(log_g)
if isinstance(log_g, u.Quantity):
raise synexceptions.SynphotError(
'Quantity is not supported for log surface gravity.')
t_eff = units.validate_quantity(_par_from_parser(t_eff), u.K).value
catdir = stio.irafconvert(catdir)
filename = os.path.join(catdir, 'catalog.fits')
# If not cached, read from grid catalog and cache it
if filename not in _CACHE:
data = stio.read_catalog(filename) # Ext 1
_CACHE[filename] = [[float(x) for x in index.split(',')] +
[data['FILENAME'][i]]
for i, index in enumerate(data['INDEX'])]
indices = _CACHE[filename]
list0, list1 = _break_list(indices, 0, t_eff)
list2, list3 = _break_list(list0, 1, metallicity)
list4, list5 = _break_list(list1, 1, metallicity)
list6, list7 = _break_list(list2, 2, log_g)
list8, list9 = _break_list(list3, 2, log_g)
list10, list11 = _break_list(list4, 2, log_g)
list12, list13 = _break_list(list5, 2, log_g)
sp1 = _get_spectrum(list6[0], catdir)
sp2 = _get_spectrum(list7[0], catdir)
sp3 = _get_spectrum(list8[0], catdir)
sp4 = _get_spectrum(list9[0], catdir)
sp5 = _get_spectrum(list10[0], catdir)
sp6 = _get_spectrum(list11[0], catdir)
sp7 = _get_spectrum(list12[0], catdir)
sp8 = _get_spectrum(list13[0], catdir)
spa1 = _interpolate_spectrum(sp1, sp2, log_g)
spa2 = _interpolate_spectrum(sp3, sp4, log_g)
spa3 = _interpolate_spectrum(sp5, sp6, log_g)
spa4 = _interpolate_spectrum(sp7, sp8, log_g)
spa5 = _interpolate_spectrum(spa1, spa2, metallicity)
spa6 = _interpolate_spectrum(spa3, spa4, metallicity)
spa7 = _interpolate_spectrum(spa5, spa6, t_eff)
sp = spa7[0]
sp.meta['expr'] = '{0}(T_eff={1:g},metallicity={2:g},log_g={3:g})'.format(
gridname, t_eff, metallicity, log_g)
return sp
def grid_to_spec(gridname, t_eff, metallicity, log_g):
"""Extract spectrum from given catalog grid parameters.
Interpolate if necessary.
Grid parameters are read with :func:`get_catalog_index`.
Parameters
----------
gridname : {'ck04models', 'k93models', 'phoenix'}
Model to use:
* ``ck04models`` - Castelli & Kurucz (2004)
* ``k93models`` - Kurucz (1993)
* ``phoenix`` - Allard et al. (2009)
t_eff : str, float or `astropy.units.quantity.Quantity`
Effective temperature of model.
If not Quantity, assumed to be in Kelvin.
If string (from parser), convert to Quantity.
metallicity : str or float
Metallicity of model.
If string (from parser), convert to float.
log_g : str or float
Log surface gravity for model.
If string (from parser), convert to float.
Returns
-------
sp : `synphot.spectrum.SourceSpectrum`
Empirical source spectrum.
Raises
------
stsynphot.exceptions.ParameterOutOfBounds
Grid parameter out of bounds.
synphot.exceptions.SynphotError
Invalid inputs.
"""
indices, catdir = get_catalog_index(gridname)
metallicity = _par_from_parser(metallicity)
if isinstance(metallicity, u.Quantity):
raise synexceptions.SynphotError(
'Quantity is not supported for metallicity.')
log_g = _par_from_parser(log_g)
if isinstance(log_g, u.Quantity):
raise synexceptions.SynphotError(
'Quantity is not supported for log surface gravity.')
t_eff = units.validate_quantity(_par_from_parser(t_eff), u.K).value
list0, list1 = _break_list(indices, 0, t_eff)
list2, list3 = _break_list(list0, 1, metallicity)
list4, list5 = _break_list(list1, 1, metallicity)
list6, list7 = _break_list(list2, 2, log_g)
list8, list9 = _break_list(list3, 2, log_g)
list10, list11 = _break_list(list4, 2, log_g)
list12, list13 = _break_list(list5, 2, log_g)
sp1 = _get_spectrum(list6[0], catdir)
sp2 = _get_spectrum(list7[0], catdir)
sp3 = _get_spectrum(list8[0], catdir)
sp4 = _get_spectrum(list9[0], catdir)
sp5 = _get_spectrum(list10[0], catdir)
sp6 = _get_spectrum(list11[0], catdir)
sp7 = _get_spectrum(list12[0], catdir)
sp8 = _get_spectrum(list13[0], catdir)
spa1 = _interpolate_spectrum(sp1, sp2, log_g)
spa2 = _interpolate_spectrum(sp3, sp4, log_g)
spa3 = _interpolate_spectrum(sp5, sp6, log_g)
spa4 = _interpolate_spectrum(sp7, sp8, log_g)
spa5 = _interpolate_spectrum(spa1, spa2, metallicity)
spa6 = _interpolate_spectrum(spa3, spa4, metallicity)
spa7 = _interpolate_spectrum(spa5, spa6, t_eff)
sp = spa7[0]
sp.meta['expr'] = (f'{gridname}(T_eff={t_eff:g},'
f'metallicity={metallicity:g},log_g={log_g:g})')
return sp
