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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 DR5 is the fifth major data release and provides images, imaging catalogs, spectra, and redshifts for download.

About DR5 explains what is new in DR5, and lists remaining or new caveats and subtleties in the data.

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.


Footprint area 8000 sq. deg.
Imaging catalog 215 million unique objects
Data volume
images9.0 TB
catalogs (DAS, fits format)1.8 TB
catalogs (CAS, SQL database)3.6 TB
Average wavelengths and magnitude limits
(95% detection repeatability for point sources)
u g r i z
3551Å 4686Å 6165Å 7481Å 8931Å
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


Spectroscopic area 5740 sq. deg.
Wavelength coverage 3800-9200Å
Resolution 1800
Signal-to-noise >4 per pixel at g=20.2
Redshift accuracy 30 km/sec rms for main galaxy sample (from repeat observations)
Target magnitude limits for main samples Galaxies: Petrosian r <17.77
Quasars: PSF i <19.1
Spectroscopic catalog 1,048,960 spectra, classified into
674,749 Galaxies
79,394 Quasars (redshift <2.3)
11,217 Quasars (redshift >2.3)
154,925 Stars
60,808 M stars and later
55,555 Sky spectra
12,312 Unknown class
Data volume
calibrated spectra ("2d")60 GB
spectra, redshifts, line measurements ("1d")170 GB

Previous data releases

For reference, we provide links to earlier data releases. The current data release always provides both the largest sky coverage and the highest-quality data and reductions.

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All DAS servers will be down the weekend of April 22, 2006 for scheduled maintenance.

Old news
Imaging Sky Image
SDSS DR5 Imaging Sky Coverage (Aitoff projection of Equatorial coordinates)

Spectral Sky Image
SDSS DR5 Spectral Sky Coverage (Aitoff projection of Equatorial coordinates)