# ObservationSpectralElement¶

class stsynphot.spectrum.ObservationSpectralElement(modelclass, obsmode=None, **kwargs)[source]

Class to handle bandpass from observation mode.

This class has additional methods that are specific to observation mode and instrument-specific wavelength set.

Note

For methods that take area, it is recommended but not required to use area.

Parameters
modelclass, kwargs
obsmodeObservationMode

Observation mode for this bandpass.

Attributes Summary

 area Telescope collecting area based on obsmode. binset Instrument-specific wavelength set from stsynphot.wavetable.WAVECAT based on obsmode. obsmode Observation mode for this bandpass.

Methods Summary

 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. bounded_by_zero([wavelengths, verbose]) Check if sampled throughout is bounded by zeroes. from_file(filename, **kwargs) Disabled. from_filter(filtername, **kwargs) Disabled. from_obsmode(obsmode[, graphtable, …]) Create a bandpass from observation mode string. Display self.obsmode optical component filenames. taper(**kwargs) Disabled. thermback([area, thermtable]) Calculate thermal background count rate for self.obsmode. to_fits(filename[, wavelengths]) Write the spectrum to a FITS file.

Attributes Documentation

area

Telescope collecting area based on obsmode.

binset

Instrument-specific wavelength set from stsynphot.wavetable.WAVECAT based on obsmode.

obsmode

Observation mode for this bandpass.

Methods Documentation

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().

Returns
npixnumber

Number of pixels.

Raises
synphot.exceptions.UndefinedBinset

Undefined binset.

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().

Returns
waverangeQuantity

Lower and upper limits of the wavelength range, in the unit of cenwave.

Raises
synphot.exceptions.UndefinedBinset

Undefined binset.

bounded_by_zero(wavelengths=None, verbose=True)[source]

Check if sampled throughout is bounded by zeroes.

Parameters
wavelengthsarray-like, Quantity, or None

Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If None, self.waveset is used.

verbosebool

Print warning if unbounded.

Returns
boundedbool

True if bounded by zeroes, False otherwise.

classmethod from_file(filename, **kwargs)[source]

Disabled.

classmethod from_filter(filtername, **kwargs)[source]

Disabled.

classmethod from_obsmode(obsmode, graphtable=None, comptable=None, component_dict={})[source]

Create a bandpass from observation mode string.

Parameters
obsmodestr

Observation mode.

graphtablestr or None

Graph table filename. If None, uses stsynphot.config.conf.graphtable.

comptablestr or None

Optical component table filename. If None, uses stsynphot.config.conf.comptable.

component_dictdict

Maps component filename to corresponding Component.

Returns
bpObservationSpectralElement

Empirical bandpass.

Raises
synphot.exceptions.SynphotError

Observation mode yields no throughput.

showfiles()[source]

Display self.obsmode optical component filenames.

Note

Similar to IRAF SYNPHOT SHOWFILES.

taper(**kwargs)[source]

Disabled.

thermback(area=None, thermtable=None)[source]

Calculate thermal background count rate for self.obsmode.

Calculation uses 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
areafloat, Quantity, or None

Area that flux covers. If not a Quantity, assumed to be in $$cm^{2}$$. If None, use area.

thermtablestr or None

Thermal component table filename. If None, uses stsynphot.config.conf.thermtable.

Returns
bgQuantity

Thermal background count rate.

Raises
stsynphot.exceptions.PixscaleNotFoundError

Undefined pixel scale for the given observation mode.

to_fits(filename, wavelengths=None, **kwargs)[source]

Write the spectrum to a FITS file.

Throughput column is automatically named ‘THROUGHPUT’. Graph and optical component tables are written to table header (not primary) under these keywords:

• GRFTABLE

• CMPTABLE

Parameters
filenamestr

Output filename.

wavelengthsarray-like, Quantity, or None

Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If None, self.waveset is used.

kwargsdict

Keywords accepted by synphot.specio.write_fits_spec().