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.
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
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
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
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
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
