  We introduce the ongoing MaStar project, which is going to construct a large,
well-calibrated, high quality empirical stellar library with more than 8000
stars covering the wavelength range from 3622 to 10,354A at a resolution of
R~2000, and with better than 3% relative flux calibration. The spectra are
taken using hexagonal fiber bundles feeding the BOSS spectrographs on the 2.5m
Sloan Foundation Telescope, by piggybacking on the SDSS-IV/APOGEE-2
observations. Compared to previous efforts of empirical libraries, the MaStar
Library will have a more comprehensive stellar parameter coverage, especially
in cool dwarfs, low metallicity stars, and stars with different [alpha/Fe].
This is achieved by a target selection method based on large spectroscopic
catalogs from APOGEE, LAMOST, and SEGUE, combined with photometric selection.
This empirical library will provide a new basis for calibrating theoretical
spectral libraries and for stellar population synthesis. In addition, with
identical spectral coverage and resolution to the ongoing integral field
spectroscopy survey of nearby galaxies --- SDSS-IV/MaNGA (Mapping Nearby
Galaxies at APO). This library is ideal for spectral modeling and stellar
population analysis of MaNGA data.
