Imaging data

Data Release 9 includes the same sky coverage as the previous data release (DR8). No new imaging data are released in DR9, but systematic errors in astrometry and proper motions introduced with DR8 have been fixed.

A screenshot of the Navigate tool. A frame
in the center shows an image of the globular cluster with red squares marking which
stars have measured spectra. A panel on the right shows magnitudes of the selected star,
with links to more data.

The Navigate tool showing globular cluster Palomar 3 (click on the image to go to the Navigate tool in this view)

The quickest way to view SDSS imaging data for an area of sky is the SkyServer Navigate tool. Navigate provides an interactive image of a given area of sky, with an overlay of catalog data for objects identified in that sky area. When you click on an object, its data appears, with links to more detailed data.

Catalog data

All imaging catalog data is available through the search tools of SkyServer. The Imaging Query Form lets you search for catalog objects by position, magnitude, and other imaging constraints. SQL Search lets you create your own search; see the SkyServer SQL Tutorial to learn how to write SQL queries. An even more flexible and powerful interface is CasJobs, which allows you to save and analyze all your search results.

Imaging files (FITS)

In addition to catalog data, SDSS also makes all its imaging available through the Science Archive Server (SAS), which can return FITS files either for single SDSS fields or in bulk. Available imaging includes not only the final output of the Imaging pipeline (calibrated frames), but also intermediate images at various stages of processing. To learn how to work with SDSS FITS images, see Understanding SDSS Imaging Data.

More information on SDSS imaging

These pages describe how to use SDSS-III imaging data. Use the links below to learn more.

Understanding SDSS imaging describes how SDSS imaging data are organized, and provides definitions for SDSS-specific terms.
Available data describes what images and imaging catalog data products are available through the SAS and CAS.
Pipeline describes how the imaging pipeline generates outputs from raw images
Image files describes the available FITS images.
Imaging catalogs describes the available imaging catalog products.
Image quality describes some quantifications of imaging quality.
Caveats describes a number of known issues regarding the images.

See Data Access for a guide on how to access DR9 data, and Available Tools for a complete list of options. This page gives quick links to some of the most common tools for accessing SDSS images.

The SDSS imaging camera took its first science quality data the night of September 19, 1998, and was the world's most productive wide-field imaging facility until its last night of science quality data on November 18, 2009. In between it took a total of around 35,000 square degrees of images, covering a unique footprint of 14,055 square degrees of sky.

For more detailed information about how SDSS data were processed, see the Algorithms section.