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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will be kept online for some time for historical reference.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 |
| images | 2.338 TB |
| catalogs | 0.462 TB |
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| Magnitude limits (95% detection repeatability for point sources) |
| u |
g |
r |
i |
z |
| 22.0 |
22.2 |
22.2 |
21.3 |
20.5 |
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| 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 |
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| Data volume |
| calibrated spectra ("2d") | 0.014 TB |
| spectra, redshifts, line measurements ("1d") | 0.039 TB |
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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.
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