SDSS Imaging

SDSS image

Optical Spectroscopy

Galaxy spectrum

Infrared Spectroscopy

Star spectrum

Welcome to the Sloan Digital Sky Survey Science Archive Server (SAS). The SDSS is a large imaging and spectroscopic survey of the Northern sky, using the Sloan Foundation 2.5m optical telescope at Apache Point Observatory in New Mexico, and is currently being extended to the Southern Sky, using the 2.5m Du Pont optical telescope at Las Campanas Observatory in Chile. 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 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 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 DR16 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. The SAS Login button (at the top right of this page) provides access to proprietary SDSS data which is not yet included in a data release, but you do not need to login to access the current data release.

An application programmatic interface (API) is also available to provide access to the data. This API allows you to directly download a single spectrum, supporting multiple formats including fits and csv. Full details and examples are available for Optical Spectrum Data Access API, and Infrared Spectrum Data Access API.