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SDSS Data Releases

Data Release 6

Sky coverage of imaging data in DR5
Sky coverage of spectroscopic data in DR5
Sky coverage of SEGUE imaging data in DR5
Sky coverage of SEGUE spectroscopic data in DR5
The Sixth Data Release (DR6) of the Sloan Digital Sky Survey is now available. The spatial coverage of DR6 is about 7% larger than that of DR5. The photometric data in DR6 are based on five-band imaging observations of 8520 square degrees of sky, and include measures of 300 million unique objects.

Based on these photometric data, objects were selected for spectroscopy over a footprint area of 6860 square degrees. DR5 includes derived spectroscopic parameters for 1,163,520 spectra, classified into 792,680 galaxies, 154,925 stars and 104,140 quasars.

DR6 also contains the first release of data from the SEGUE (Sloan Extension for Galactic Understanding and Exploration) program, which is one of the three components of SDSS-II: the Legacy Survey, SEGUE and the SuperNova Survey.

The SEGUE imaging data is available in a separate database in the CAS, SegueDR6, whereas the SEGUE spectra are part of the main database, BestDR6. You can browse SEGUE imaging data on the SEGUE SkyServer site. The SEGUE spectra are in the special SEGUE plates in the BestDR6 database.

Further details of the Data Release 6 can be found at http://www.sdss.org/dr6/.

Data Release 5

Sky coverage of imaging data in the DR5
Sky coverage of spectroscopic data in the DR5
The Sloan Digital Sky Survey has released its fifth Data Release (DR5). The spatial coverage of DR5 is about 20% larger than that of DR4. The photometric data in DR5 are based on five-band imaging observations of 8000 square degrees of sky, and include measures of 215 million unique objects.

Based on these photometric data, objects were selected for spectroscopy over a footprint area of 5740 square degrees. DR5 includes derived spectroscopic parameters for 1,048,960 spectra, classified into 674,749 galaxies, 192,982 stars and 90,611 quasars.

Details of the Data Release 5 can be found at http://www.sdss.org/dr5/.

Data Release 4

Sky coverage of imaging data in the DR4
Sky coverage of spectroscopic data in the DR4
Data Release 4 (DR4) went public in June 2005. The spatial coverage of DR4 is about 25% larger than that of DR3. The photometric data in DR4 are based on five-band imaging observations of 6670 square degrees of sky, and include measures of 180 million unique objects.

Based on these photometric data, objects were selected for spectroscopy over a footprint area of 5320 square degrees. DR4 includes these spectra, with derived spectroscopic parameters, for 672,640 objects. DR4 also includes on additional 133,760 spectra of objects selected using a variety of alternative algorithms.

Details of the Data Release 4 can be found at http://www.sdss.org/dr4/.

Data Release 3

Sky coverage of imaging data in the DR3
Sky coverage of spectroscopic data in the DR3
The Sloan Digital Sky Survey has released its third Data Release (DR3). DR3 is about 1.6 times the size of DR2 in spatial coverage. The photometric data in DR3 are based on five-band imaging observations of 5282 square degrees of sky, and include measures of 141 million unique objects.

Based on these photometric data, objects were selected for spectroscopy over a footprint area of 4188 square degrees. DR3 includes these spectra, with derived spectroscopic parameters, for 528,640 objects.

Details of the Data Release 3 can be found at http://www.sdss.org/dr3/.

Data Release 2

Sky coverage of imaging data in the DR2
Sky coverage of spectroscopic data in the DR2
The Sloan Digital Sky Survey released its second Data Release (DR2) in March 2004. DR2 is about 1.5 times the size of DR1 in spatial coverage. The photometric data in DR2 are based on five-band imaging observations of 3324 square degrees of sky, and include measures of 88 million unique objects.

Based on these photometric data, objects were selected for spectroscopy to a surface density of about 120 extragalactic candidates per square degree. DR2 includes these spectra, with derived spectroscopic parameters, for over 295,000 galaxies and quasars.

Details of the Data Release 2 can be found at http://www.sdss.org/dr2/.

Data Release 1

Sky coverage of imaging data in the DR1
Sky coverage of spectroscopic data in the DR1
The first official Data Release (DR1) of SDSS was in June 2003. DR1 includes reprocessed data from the Early Data Release. (Reprocessing means that the data are not exactly identical from the EDR, however.) The photometric data in DR1 are based on five-band imaging observations of 2099 square degrees of sky, and include measures of 53 million unique objects.

DR1 includes spectroscopic parameters for over 150,000 galaxies and quasars.

Details of the Data Release 1 can be found at http://www.sdss.org/dr1/.

The Early Data Release

Sky coverage of imaging data in the EDR
Sky coverage of spectroscopic data in the EDR
The Early Data Release of the Sloan Digital Sky Survey consists of five-band images and measured parameters for all detected sources, as well as spectra, redshifts and other spectroscopic parameters. While these data are derived from commissioning observing runs, the quality of the data and calibrations already support a wide range of scientific applications.

The available data products include: a searchable catalog containing the detected objects and their associated image and spectral parameters or attributes, 3-color pictures in JPEG format, data images in FITS format, and spectra in both GIF and FITS format. The EDR covers about 462 square degrees.