SDSS Multi-Object Spectrographs

General Notes

The SDSS uses two identical multi-object fiber spectrographs permanently mounted near the Cassegrain focus of the 2.5 m telescope at Apache Point Observatory (Photo).

SPECTROGRAPH CHARACTERISTICS

Number of spectrographs	2
Spectral resolution	1800
Wavelength coverage	3900 - 9100 Angstroms in two channels
Blue channel range	3900 - 6000 Angstroms
Red channel range	6000 - 9100 Angstroms
Fiber inputs per spectrograph	320
Telescope aperture	2.5 m
Fiber diameter	180 microns (3 arc seconds)
Telescope f-ratio	5
Spectrograph f-ratio (fiber output beam)	4
Beam size	6 inches diameter
Demag ratio	2.5

Optics

Throughput

Mechanical

Feb 2000 Dark Tests

Maintenance

Warming the CCDs

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