Welcome to the Sloan Digital Sky Survey III Science Archive Server. The SDSS-III is a large imaging and spectroscopic survey of the Northern sky, using a 2.5m optical telescope at Apache Point Observatory in New Mexico. The SAS serves images and spectra generated by the survey to astronomers and the general public alike. Please see the main survey site for full details and documentation.
The main goal of SAS is to serve the binary image files and full spectroscopic results (i.e., flux versus wavelength). For catalogs and derived parameters, we recommend instead using the the SDSS-III SkyServer and the associated CASJobs database.
Links on the menu above will guide you through the SAS tools for finding, displaying and downloading images and spectra. Understanding the basics of SDSS imaging, optical spectroscopy and infrared (IR) spectroscopy is crucial for using these tools sensibly. Example images and spectra are above, with links into the SAS pages that search for them.
The SAS also provides direct links into the directory tree containing the full DR12 data set in the form of flat files. These files are only for the real experts! Please see the data access tools documentation as well as the data model for full details.