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The Sloan Digital Sky Survey (see www.sdss.org for general information) will map one-quarter of the entire sky and perform a redshift survey of galaxies, quasars and stars. The DR1 is the first major data release and provides images, imaging catalogs, spectra, and redshifts for download.

As of September 27 2004, Data Release 3 (DR3) is available, with more sky coverage and better reductions. We strongly encourage you to use DR3 data. The DR1 site will be kept online for some time for historical reference.

We discovered during testing of the DR1 data set that the photometric pipeline suffered from a bug in the computation of model magnitudes and scale radii. About DR1 explains the effect of the bug. DR3 contains a reprocessing of the DR1 data with a new version of the photometric pipeline.

Please refer to the credits page for our sources of funding, participating institutions, how to acknowledge the use of SDSS data in your publications. Please also note how to refer to SDSS sources in your publications using the proper IAU nomenclature for SDSS sources.

Imaging

Footprint area 2099 sq. deg.
Imaging catalog 53 million unique objects
Data volume
images2.338 TB
catalogs0.462 TB
Magnitude limits (95% detection repeatability for point sources)
u g r i z
22.0 22.2 22.2 21.3 20.5
PSF width 1.4" median in r
Photometric calibration
r u-g g-r r-i i-z
2% 3% 2% 2% 3%
Astrometry < 0.1" rms absolute per coordinate

Spectroscopy

Spectroscopic area 1360 sq. deg. (Note: we earlier erroneously reported 1556 sq. deg. as spectroscopic area.)
Resolution 1800
Signal-to-noise >4 per pixel at g=20.2
Redshift accuracy 30 km/sec rms (from repeat observations)
Target magnitude limits for main samples Galaxies: Petrosian r <17.77
Quasars: PSF i <19.1
Spectroscopic catalog 186,250 objects, classified into
134,000 Galaxies
17,700 Quasars (redshift <2.3)
980 Quasars (redshift >2.3)
17,600 Stars
4500 M stars and later
9700 Sky spectra
1770 Unknown class
Data volume
calibrated spectra ("2d")0.014 TB
spectra, redshifts, line measurements ("1d")0.039 TB

This is version v20041013_1341 .

If you are using Netscape 4.x and see oversized fonts, please look at the workaround on the Credits page.

News: DR3 is available. More...
Imaging Sky Image
SDSS DR1 Imaging Sky Coverage (Aitoff projection of Equatorial coordinates)

Spectral Sky Image
SDSS DR1 Spectral Sky Coverage (Aitoff projection of Equatorial coordinates)