Observation¶

class
synphot.observation.
Observation
(spec, band, binset=None, force='none')[source]¶ Bases:
synphot.spectrum.BaseSourceSpectrum
This is an observed spectrum, where a source spectrum has gone through a bandpass.
Usually, this is the end point of a chain of spectral manipulation. It has extra attributes that deal with binning, which is introduced by the detector.
 Parameters
 spec
SourceSpectrum
orspecutils.Spectrum1D
Source spectrum.
 band
SpectralElement
Bandpass.
 binsetarraylike,
Quantity
, orNone
Center of binned wavelengths. If not a Quantity, assumed to be in Angstrom. If
None
, inputself.waveset
values are used. force{
None
, ‘none’, ‘extrap’, ‘taper’} Force creation of an observation even when source spectrum and bandpass do not fully overlap:
None
or ‘none’  Source must encompass bandpass (default)‘extrap’  Extrapolate source spectrum (this changes the underlying model of
spec
to always extrapolate, if applicable)‘taper’  Taper source spectrum
 spec
 Raises
 synphot.exceptions.DisjointError
Bandpass does not overlap with source spectrum.
 synphot.exceptions.PartialOverlap
Bandpass only partially overlaps with source spectrum when they must fully overlap.
 synphot.exceptions.SynphotError
Invalid inputs.
 synphot.exceptions.UndefinedBinset
Missing binned wavelength set.
Attributes Summary
Bandpass of the observation.
Edges of binned wavelengths.
Binned flux corresponding to
binset
.Center of binned wavelengths.
Source spectrum of the observation.
Methods Summary
as_spectrum
([binned, wavelengths])Reduce the observation to an empirical source spectrum.
binned_pixelrange
(waverange, **kwargs)Calculate the number of pixels within the given wavelength range and
binset
.binned_waverange
(cenwave, npix, **kwargs)Calculate the wavelength range covered by the given number of pixels centered on the given central wavelengths of
binset
.countrate
(area[, binned, wavelengths, …])Calculate effective stimulus in count/s.
effective_wavelength
([binned, wavelengths, mode])Calculate effective wavelength.
effstim
([flux_unit, wavelengths, area, vegaspec])Calculate effective stimulus for given flux unit.
plot
([binned, wavelengths, flux_unit, area, …])Plot the observation.
sample_binned
([wavelengths, flux_unit])Sample binned observation without interpolation.
taper
(**kwargs)Tapering is disabled.
Attributes Documentation

bandpass
¶ Bandpass of the observation.

bin_edges
¶ Edges of binned wavelengths.

binset
¶ Center of binned wavelengths.

spectrum
¶ Source spectrum of the observation.
Methods Documentation

as_spectrum
(binned=True, wavelengths=None)[source]¶ Reduce the observation to an empirical source spectrum.
An observation is a complex object with some restrictions on its capabilities. At times, it would be useful to work with the observation as a simple object that is easier to manipulate and takes up less memory.
This is also useful for writing an observation as sampled spectrum out to a FITS file.
 Parameters
 Returns
 sp
SourceSpectrum
Empirical source spectrum.
 sp

binned_pixelrange
(waverange, **kwargs)[source]¶ Calculate the number of pixels within the given wavelength range and
binset
. Parameters
 waverangetuple of float or
Quantity
Lower and upper limits of the desired wavelength range. If not a Quantity, assumed to be in Angstrom.
 kwargsdict
Keywords accepted by
synphot.binning.pixel_range()
.
 waverangetuple of float or
 Returns
 npixint
Number of pixels.

binned_waverange
(cenwave, npix, **kwargs)[source]¶ Calculate the wavelength range covered by the given number of pixels centered on the given central wavelengths of
binset
. Parameters
 cenwavefloat or
Quantity
Desired central wavelength. If not a Quantity, assumed to be in Angstrom.
 npixint
Desired number of pixels, centered on
cenwave
. kwargsdict
Keywords accepted by
synphot.binning.wave_range()
.
 cenwavefloat or
 Returns
 waverange
Quantity
Lower and upper limits of the wavelength range, in the unit of
cenwave
.
 waverange

countrate
(area, binned=True, wavelengths=None, waverange=None, force=False)[source]¶ Calculate effective stimulus in count/s.
 Parameters
 areafloat or
Quantity
Area that flux covers. If not a Quantity, assumed to be in \(cm^{2}\).
 binnedbool
Sample data in native wavelengths if
False
. Else, sample binned data (default). wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. This must be given if
self.waveset
is undefined for the underlying spectrum model(s). If not a Quantity, assumed to be in Angstrom. IfNone
,self.waveset
orbinset
is used, depending onbinned
. waverangetuple of float, Quantity, or
None
Lower and upper limits of the desired wavelength range. If not a Quantity, assumed to be in Angstrom. If
None
, the full range is used. forcebool
If a wavelength range is given, partial overlap raises an exception when this is
False
(default). Otherwise, it returns calculation for the overlapping region. Disjoint wavelength range raises an exception regardless.
 areafloat or
 Returns
 count_rate
Quantity
Observation effective stimulus in count/s.
 count_rate
 Raises
 synphot.exceptions.DisjointError
Wavelength range does not overlap with observation.
 synphot.exceptions.PartialOverlap
Wavelength range only partially overlaps with observation.
 synphot.exceptions.SynphotError
Calculation failed.

effective_wavelength
(binned=True, wavelengths=None, mode='efflerg')[source]¶ Calculate effective wavelength.
 Parameters
 binnedbool
Sample data in native wavelengths if
False
. Else, sample binned data (default). wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If
None
,self.waveset
orbinset
is used, depending onbinned
. mode{‘efflerg’, ‘efflphot’}
Flux is first converted to the unit below before calculation:
‘efflerg’  FLAM
‘efflphot’  PHOTLAM (deprecated)
 Returns
 eff_lam
Quantity
Observation effective wavelength.
 eff_lam
 Raises
 synphot.exceptions.SynphotError
Invalid mode.

effstim
(flux_unit=None, wavelengths=None, area=None, vegaspec=None)[source]¶ Calculate effective stimulus for given flux unit.
 Parameters
 flux_unitstr or
Unit
orNone
The unit of effective stimulus. COUNT gives result in count/s (see
countrate()
for more options). If not given, internal unit is used. wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. This must be given if
self.waveset
is undefined for the underlying spectrum model(s). If not a Quantity, assumed to be in Angstrom. IfNone
,self.waveset
is used. area, vegaspec
See
convert_flux()
.
 flux_unitstr or
 Returns
 eff_stim
Quantity
Observation effective stimulus based on given flux unit.
 eff_stim

plot
(binned=True, wavelengths=None, flux_unit=None, area=None, vegaspec=None, **kwargs)[source]¶ Plot the observation.
Note
Uses
matplotlib
. Parameters
 binnedbool
Plot data in native wavelengths if
False
. Else, plot binned data (default). wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If
None
,self.waveset
orbinset
is used, depending onbinned
. flux_unitstr or
Unit
orNone
Flux is converted to this unit for plotting. If not given, internal unit is used.
 area, vegaspec
See
convert_flux()
. kwargsdict
 Raises
 synphot.exceptions.SynphotError
Invalid inputs.

sample_binned
(wavelengths=None, flux_unit=None, **kwargs)[source]¶ Sample binned observation without interpolation.
To sample unbinned data, use
__call__
. Parameters
 Returns
 flux
Quantity
Binned flux in given unit.
 flux
 Raises
 synphot.exceptions.InterpolationNotAllowed
Interpolation of binned data is not allowed.