SDSSugriz
SDSSugriz refers to the five-band optical photometric system used by the Sloan Digital Sky Survey. The system comprises five broad-band filters, labeled u, g, r, i, and z, designed to span from near-ultraviolet to near-infrared and to provide color information that aids in object classification and redshift estimation.
The approximate effective wavelengths are u ≈ 355 nm, g ≈ 468 nm, r ≈ 616 nm, i ≈ 748
SDSS ugriz photometry has been central to studies of stars, galaxies, and quasars, enabling color-based selection