The BaSeL Stellar Libraries  
Spectrophotometric and Photometric Evolution of Galaxies 
The BaSeL stellar spectral energy distribution (SED) libraries are libraries of theoretical stellar SEDs recalibrated using empirical photometric data. Therefore, we call them semi-empirical libraries. They cover a wide range of stellar parameters and are widely used for a variety of applications, such as evolutionary population synthesis.
There are two versions currently in use: The BaSeL 2.2 library (Lejeune, Cuisiner, and Buser, 1998 A&AS, 130, 65) which was calibrated using photometric data from solar metallicity stars.
The BaSeL 2.2 library can be downloaded here.
The BaSeL 3.1 library (Westera, Lejeune, Buser, Cuisinier, and Bruzual A., 2002 A&A, 381, 524) was calibrated metallicity-dependently using photometric data from globular clusters.
The BaSeL 3.1 library can be downloaded here.

The libraries can also be retrieved via public ftp from the Observatório do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil:
ftp://ftp.ov.ufrj.br/pub/westera/,
and the Universidade Estadual de Santa Cruz, Ilhéus, Brazil:
http://astro.uesc.br/~pieter/downloads/.

For further information on the BaSeL libraries, please read Lejeune, Cuisiner, and Buser (1997 A&AS, 125, 229, 1998 A&AS, 130, 65) and Westera, Lejeune, Buser, Cuisinier, and Bruzual A. (2002 A&A, 381, 524).  
Project Management 
Roland Buser, Prof. Dr. phil.
Collaborators  Institution 
Pieter Westera, Prof. Adj. Dr. Universidade Estadual de Santa Cruz, Ilhéus, Brazil
François Cuisinier, Prof. Adj. Dr. Observatório do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  Funding 
  Swiss National Science Foundation SNSF