The Bayesian Extinction and Stellar Tool (BEAST) is a Python package that fits the ultraviolet to near-infrared photometric SEDs of stars to extract stellar and dust extinction parameters. The stellar parameters are age (t), mass (M), metallicity (M), and distance (d). The dust extinction parameters are dust column (Av), average grain size (Rv), and mixing between type A and B extinction curves (fA).

The full details of the BEAST are provided by Gordon et al. (2016, ApJ, 826, 104):…826..104G

Getting started

User Documentation




A list of publications using the BEAST, can be found here.

Reporting Issues

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

More details on how to contribute to the beast can be found in the Developer Documentation:

For the complete list of contributors, please see the beast contributors page on Git/hub.

Reference API