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A new low-to-moderate resolution spectrograph has been designed and built for the Cassegrain focus of the Hale 5.08meter telescope. To maximize efficiency, resolution, and wavelength coverage the light is divided into two spectral regions by a dichroic filter behind the entrance slit, after which there are two completely separate spectrographs. The blue spectrograph operates from 3200 Â to 5200 Á while the red one goes from 5200 Â to 10,000 Á. The red detector is an 800 X 800 TI CCD while the blue detector is a 320 X 512 RCA CCD or a Shectrograph image pulse-counting system. A Boksenberg IPCS can also be mounted on the blue camera. The overall efficiency of the Cassegrain telescope, spectrographs, and CCD's combined, ranges from 5% to 13% between 3600 Á and 8200 Â. The spectrograph is usable from 3200 Â to 10,400 Á.

The Early Data Release from the Sloan Digital Sky survey provides one of the largest multicolor photometric catalogs currently available to the astronomical community. In this paper we present the first application of photometric redshifts to the ∼ 6 million extended sources within these data (with 1.8 million sources having r ′ < 21). Utilizing a range of photometric redshift techniques, from empirical to template and hybrid techniques, we investigate the statistical and systematic uncertainties present within the redshift estimates for the EDR data. For r ′ < 21 we find that the redshift estimates provide realistic redshift histograms with an rms uncertainty in the photometric redshift relation of 0.035 at r ′ < 18 and rising to 0.1 at r ′ < 21. We conclude by describing how these photometric redshifts and derived quantities, such as spectral type, restframe colors and absolute magnitudes, are stored within the SDSS database. We provide sample queries for searching on photometric redshifts and list the current caveats and issues that should be understood before using these photometric redshifts in statistical analyses of the SDSS galaxies.

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