Data Release 4 |
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| Sky coverage of imaging data in the DR4 |
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Sky coverage of spectroscopic data in the DR3 |
The Sloan Digital Sky Survey has released its fourth Data Release (DR4).
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. DR3 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/. See
also the release notes for DR4.
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Data Release 3 |
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| Sky coverage of imaging data in the DR3 |
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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/. See
also the release notes for DR3.
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Data Release 2 |
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| Sky coverage of imaging data in the DR2 |
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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/.
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Data Release 1 |
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| Sky coverage of imaging data in the DR1 |
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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/.
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The Early Data Release |
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| Sky coverage of imaging data in the EDR |
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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.
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