Measure Extinction

measure_extinction is a python package to measure extinction due to dust absorbing photons or scattering photons out of the line-of-sight. Extinction applies to the case for a star seen behind a foreground screen of dust. This package provides the tools to measure dust extinction curves using observations of two effectively identical stars, differing only in that one is seen through more dust than the other.

Models of the wavelength dependence of dust extinction can be found in the dust_extinction package. More complex geometries of stars and dust include additional radiative transfer effects resulting in attenuation. Models of the wavelength dependence of dust attenuation can be found in the dust_attenuation package.

This package is developed in the astropy affiliated package template.

Reporting Issues

If you have found a bug in measure_extinction please report it by creating a new issue on the measure_extinction GitHub issue tracker.

Please include an example that demonstrates the issue sufficiently so that the developers can reproduce and fix the problem. You may also be asked to provide information about your operating system and a full Python stack trace. The developers will walk you through obtaining a stack trace if it is necessary.


Like the Astropy project, the measure_extinction is made both by and for its users. We accept contributions at all levels, spanning the gamut from fixing a typo in the documentation to developing a major new feature. We welcome contributors who will abide by the Python Software Foundation Code of Conduct.

measure_extinction follows the same workflow and coding guidelines as Astropy. The following pages will help you get started with contributing fixes, code, or documentation (no git or GitHub experience necessary):

For the complete list of contributors please see the measure_extinction contributors page on Github.

Reference API

measure_extinction.stardata Module


StarData(datfile[, path, photonly, use_corfac])

Photometric and spectroscopic data for a star


Photometric band data (used by StarData)


Spectroscopic data (used by StarData)

Class Inheritance Diagram

Inheritance diagram of measure_extinction.stardata.StarData, measure_extinction.stardata.BandData, measure_extinction.stardata.SpecData

measure_extinction.modeldata Module


ModelData(modelfiles[, path, band_names, …])

Provide stellar atmosphere model “observed” data given input stellar, gas, and dust extinction parameters.

Class Inheritance Diagram

Inheritance diagram of measure_extinction.modeldata.ModelData

measure_extinction.extdata Module


AverageExtData(extdatas[, alav])

Generate the average extinction curve from a list of ExtData objects



Extinction for a single line-of-sight

Class Inheritance Diagram

Inheritance diagram of measure_extinction.extdata.ExtData

measure_extinction.merge_obsspec Module


merge_iue_obsspec(obstables[, output_resolution])

Merge one or more IUE 1D spectra into a single spectrum on a uniform wavelength scale

merge_stis_obsspec(obstables[, waveregion, …])

Merge one or more STIS 1D spectra into a single spectrum on a uniform wavelength scale

merge_irs_obsspec(obstables[, output_resolution])

Merge one or more Spitzer IRS 1D spectra into a single spectrum on a uniform wavelength scale

merge_spex_obsspec(obstable[, output_resolution])

Merge one or more IRTF SpeX 1D spectra into a single spectrum on a uniform wavelength scale