Scientists from Johns Hopkins are responsible for construction of two spectrographs and for the science data archive for all data. Two large, dual-channel spectrographs cover the wide wavelength range from the ultraviolet to the infrared. Each is fed with 320 fibers aligned with astronomical objects in the telescope's focal plane. The entire spectroscopic system allows the measuring of 640 spectra per hour of observation time. Red shifts determined from the data provide distances to quasars and galaxies, the third dimension of the Sky Survey.

Making the enormous volume of data from the Sky Survey available for study is an important challenge of the collaboration. Scientists from Johns Hopkins have responsibility for the design of the science database and of the user interfaces for accessing it. The terabyte database consists of an electronic archive of information from the operations database created from the data pipelines, in a format readily accessible to Survey scientists and others.

Participants from Johns Hopkins:

* denotes a Builder of the SDSS.