Eric H. Neilsen

TL;DR: The Sloan Digital Sky Survey (SDSS) as discussed by the authors provides the data to support detailed investigations of the distribution of luminous and non-luminous matter in the universe: a photometrically and astrometrically calibrated digital imaging survey of π sr above about Galactic latitude 30° in five broad optical bands to a depth of g' ~ 23 mag.

TL;DR: A series of improvements to the spectroscopic reductions are described, including better flat fielding and improved wavelength calibration at the blue end, better processing of objects with extremely strong narrow emission lines, and an improved determination of stellar metallicities.

TL;DR: The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of ≈106 galaxies, 100,000 quasars, 30,000 stars, and 30, 000 serendipity targets as discussed by the authors.

TL;DR: The Sloan Digital Sky Survey (SDS) as discussed by the authors is a two-corrector Ritchey-Chretien design with a 2.5 m, f/2.25 m, a 1.08 m secondary, and one of a pair of interchangeable highly aspheric correctors near the focal plane, one for imaging and the other for spectroscopy.