Data Access for SDSS DR12 Overview

Data Release 12 includes five types of data: images, optical spectra, infrared spectra, stellar interferometry, and catalog data (parameters measured from images and spectra, such as magnitudes and redshifts). The SDSS web sites offer several different online data access tools, each suited to a particular need. The primary websites, described in more detail in the Available Tools page, are:

Primary Websites

Website
Purpose
www.sdss4.org/dr12
DR12 Documentation (this site)
dr12.sdss3.org
Science Archive Server (SAS): interactive spectra and image mosaics
data.sdss3.org/sas/dr12
Direct download access to DR12 data files for experts
data.sdss3.org/datamodel
Details of the SAS directory structure, file formats, and the contents of each file
skyserver.sdss.org/dr12
SkyServer: Browser-based access to the Catalog Archive Server (CAS) database, with resources for learning SQL and projects to teach science
skyserver.sdss.org/casjobs
Flexible advanced SQL-based interface to the CAS, for all data releases

The tables below provide links to the appropriate tools for various common tasks. The first column describes something you might need to do with SDSS data, and the second column links to the best tool to do that. If your question isn’t addressed here, please look at the Frequently Asked Questions and/or Tutorials help pages.

If you are having difficulty connecting to any data server, please check the status page for announcements about planned outages.

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Images

The SDSS has taken deep images of more than one-third of the entire night sky. You can view SDSS images online for any object or sky position in the survey area, and download images of SDSS fields as FITS files. Since some stars were targeted for APOGEE infrared spectroscopy using 2MASS survey data, we also offer access to 2MASS images. Data from the SDSS-II Supernova Survey is not available in DR10, but is available in its entirety at the SDSS-II Supernova Survey website.

I need to…
Tool to use
browse through sky images to look for interesting objects:
Navigate
create a finding chart for my telescope using SDSS imaging:
Finding chart
download FITS images for a specific SDSS field containing a given object or sky position:
Imaging (FITS) Field Search
download FITS images for many SDSS fields:
Bulk Imaging (FITS) Search
see thumbnail images for a list of objects, or for objects matching search criteria:
Image List
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Optical Spectra

DR12 includes all optical spectra from the original SDSS-I/-II, SEGUE, and BOSS.

I need to…
Tool to use
know whether SDSS has measured an optical spectrum for my object:
Navigate
see the optical spectrum for my object:
Spectrum Search
download the FITS file with the optical spectrum for my object:
Spectrum Search
get 50,000 spectra:
See the bulk download documentation
know which optical spectroscopic data files are available:
Spectroscopic pipeline description
understand the format of a specific data file:
Data Model
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APOGEE Spectra

DR12 includes all APOGEE Infrared spectra.

I need to…
Tool to use
know whether the SDSS has measured an infrared spectrum for my object:
Navigate
see the infrared spectrum for my object:
Basic Spectrum Search
browse infrared spectra for many objects:
Bulk Spectrum Search
get 50,000 spectra:
See the bulk download documentation
know which APOGEE spectra data files are available:
Spectroscopic pipeline description
get all measured parameters for all APOGEE stars at once:
allStar and allVisit files
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MARVELS Spectra

DR12 includes all MARVELS Interferometry spectra.

I need to…
Tool to use
know whether the SDSS has measured an infrared spectrum for my object:
Navigate
see the infrared spectrum for my object:
Basic Spectrum Search
browse infrared spectra for many objects:
Bulk Spectrum Search
get 50,000 spectra:
See the bulk download documentation
know which MARVELS spectra data files are available:
Spectroscopic pipeline description
understand the format of a specific data file:
Data Model
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Catalog Data

Catalog data summarize quantities measured from the images and spectra such as magnitudes, redshifts, and object classifications. These are available either from the Catalog Archive Server (CAS) database or as binary tables in FITS file format.

I need to…
Tool to use
find all objects which match some simple selection criteria:
SkyServer SQL Search
learn how to write SQL queries:
SQL Tutorial or SQL in SkyServer or Sample Queries
perform a complicated, CPU-intensive query of SDSS catalog data:
CasJobs
generate my own database with custom tables of a subset of SDSS data:
CasJobs
understand the CAS database schema:
Schema Browser
download fits files with the catalog data:
See the bulk download documentation
understand the format of a specific catalog data file:
Data Model
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