SDSS filters (All dielectric coating)

SDSS (Sloan Digital Sky Survey) is one of the most common and important photometric systems in modern astronomy.
The large volume of survey data gotten by the SDSS project became the cultural legacy. Broad band filters currently installed in the wide field camera were generally designed on the basis of the SDSS photometric system.

Asahi provided the world's first SDSS u, g, r, i, z-band filters to Apache Points Observatory in New Mexico over twenty years ago.
The original SDSS filters were produced by the combination of colored glass and interference coatings.

Recently the new SDSS filters with higher efficiency are preferred and required, even if the bluer slope in passband is not similar to the specified colored glass.
We achieved the higher transmission and flat passband by all dielectric coatings and our proprietary magnetron sputtering technology.

figure SDSS filters for HiPERCAM at GTC