Optical Filters

Optical Instruments
International Agency
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SDSS (Sloan) filters

Sloan Digital Sky Survey (SDSS) is one of the most common and important photometric systems in modern astronomy.
The large volume of survey data gotten by the SDSS team became the cultural legacy. Broad bandpass filters installed
in the wide field cameras are defined on the basis of SDSS photometric system.

Asahi provided the world's first SDSS (Sloan) u, g, r, i, z-band filters to SDSS 2.5 m telescope at Apache Point Observatory (APO)
in New Mexico twenty years ago.
Unlike SDSS filters sold on internet, we produce under the spectral response in the 2.5 m telescope as SDSS project suggested.

Caution: "Incorrect" SDSS filters in terms of cut-on/off wavelengths are sometimes found on the website.
For example, "broad bandpass type" z-band filter is sold by some vendors, but different from the orignal z-band definition by the SDSS team.

figure SDSS Filters / u, g, r, i, z-band