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Tools for data access

DR7 data are distributed via the Catalog Archive Server (CAS), an SQL database with fast search capabilities, and the Data Archive Server (DAS), a collection of fits images and tables containing the outputs of the imaging and spectroscopic reduction pipelines. In addition, the SDSS collaboration has created catalogs and other data products based on public survey data that we link from our Value Added Data Products page.

Catalog Archive Server (CAS) Search

Web interfaces

Catalog Archive Server (DR7 CAS) The Catalog Archive Server offers efficient search tools for querying the imaging and spectro catalogs from SDSS, including SEGUE and the stripe82 coadd. There are multiple entry URLs for using the visual tools and query forms for the different databases:
cas.sdss.org/astrodr7/ Legacy and SEGUE-area imaging and all spectra
cas.sdss.org/seguetarg/ Target-era imaging data from low-galactic latitude SEGUE area
cas.sdss.org/stripe82/ Stripe 82 coadd imaging (greyscale jpegs only)
cas.sdss.org/runs/ Images and object tables from most SDSS images ever taken, including multi-epoch and supernova data from stripe82
Below, we just link to the Legacy versions of the search and browse interface, but they exist analogously for all data sets. For SQL queries, the different URLs just use different default databases, but all others are selectable via the usual syntax.
Spectro Query Server Search spectra by position, or by spectral or photometric parameters. Retrieve survey files.
Imaging Query Server Search photometry catalog by position or by photometric parameters. Retrieve survey files.
SpecList Upload plate,MJD,fiber list as part of a SQL query
Imaging cross-ID Find SDSS matches for a list of objects.
SQL search Directly search the database using your own SQL queries (also see skyserver help pages).
CasJobs Use this batch job server for direct SQL searches of the database with generous timeout setting. Share result sets with your collaborators. Access to BEST, TARGET, SEGUE verions of sky.
Navigate Point and click on SDSS images.
Finding charts Generate jpeg finding charts from SDSS images.
Image lists Get jpeg cutouts of SDSS imaging for object lists with link to finding chart. Option to generate object list from SQL query.

Query clients

In addition to using the web interfaces above, you can directly connect to the database server to perform your own SQL queries using these clients.

sqlcl python script to submit SQL queries from the command-line
skyserver.el Submit SQL queries from an emacs buffer

Data Archive Server (DAS)

The DAS contains

  • images of the night sky ("corrected frames") in fits and jpeg format
  • calibrated object lists with photometric parameters as fits binary tables
  • reduced spectra and spectral parameters as fits binary tables and ps/gif plots, both individually and bundled for mass download.

Files and directories within the DAS are designated by survey identifiers of the desired data: run/rerun/camcol/field for imaging; plate/MJD/fiberID for spectroscopy. The easiest way to obtain this designation is by one of the query forms provided. See the DAS quick reference and the the DAS structure and contents pages for what it contains.

Search & Retrieve

DAS Coordinate search Find the imaging fields corresponding to a list of (list of) RA, Dec. coordinates
DR7 DAS retrieval form Retrieve data for lists of object positions, or photometric or spectroscopic SDSS ids (e.g. run/camcol/field or plate/fiber) generated via one of the query forms above. The coverage page explains runs, reruns etc.
Direct access to Imaging / Spectro runs. For spectra, try: 2d_26 for plate files, latest sprerun.
Recommended method for retrieving all Imaging or Spectro data. Use your web browser or other http clients like wget.

This page was last modified on $Date: 2008/12/19 19:39:24 $ (UT).