The Sloan Digital Sky Survey is the deepest large scale survey of the sky currently available. SkyView dynamically queries the SDSS archive (current release DR16) to retrieve data and resample it into the user requested frame. All releases after DR9 are spectra only, so all imaging data originates from DR9. Further information about SDSS and many additional services are available at the <a href="https://www.sdss.org">SDSS website</a>. Provenance: Sloan Digital Sky Survey Team. This is a service of NASA HEASARC.