Astro Data Lab

The Legacy Surveys data and database are accessible from the Astro Data Lab, and from the Legacy Surveys team website. Explore the dataset interactively using the Sky Viewer.

Data Lab Table Access Protocol (TAP) service

TAP provides a convenient access layer to the Legacy Surveys catalog database. TAP-aware clients (such as TOPCAT) can point to https://datalab.noirlab.edu/tap. DR10, DR9, and DR8 databases are respectively named ls_dr10, ls_dr9, and ls_dr8. Select a database in order to see the tables it contains as well as their descriptions. Please note that the data model has changed slightly between DR10 and other releases so the tables and columns are not identical.

Another way to view the tables is through the Data Lab Query Interface (https://datalab.noirlab.edu/query.php). From the Column Information tab, select ls_dr10 from the left-hand menu to see the list of tables for DR10, respectively. Clicking on a table will show the column names and description. For example, ls_dr9.tractor, ls_dr9.tractor_n, ls_dr9.tractor_s correspond to the main Tractor photometry tables covering, respectively, to the full combined footprint, the North footprint (_n), and the South footprint (_s).

Data Lab Query Client

The Query Client is available as part of the Data Lab software distribution. The Query Client provides a Python API to Data Lab database services. For the Legacy Surveys, these services include anonymous, and authenticated access through synchronous or asynchronous queries of the catalog made directly to the database. Additional Data Lab services for registered users include personal database storage, and storage through the Data Lab VOSpace.

The Query Client can be called from a Jupyter Notebook on the Data Lab Notebook server. Example notebooks are provided to users upon creation of their user account (register here).

Image cutouts

The Data Lab Simple Image Access (SIA) service provide users with a fast way to retrieve cutouts from Legacy Surveys images. See the How to use the Simple Image Access (SIA) service Jupyter Notebook.

In addition, sections of the Legacy Surveys can be obtained as JPEGs or FITS files using the Legacy Surveys team cutout service, as follows:

DR10:
JPEG:   https://www.legacysurvey.org/viewer/cutout.jpg?ra=216.0276&dec=34.8592&layer=ls-dr10&pixscale=1.00&bands=griz

FITS:   https://www.legacysurvey.org/viewer/cutout.fits?ra=216.0276&dec=34.8592&layer=ls-dr10&pixscale=1.00

where "bands" is a string such as "griz","grz","g", etc. Replacing layer=ls-dr10 with layer=ls-dr10-model or layer=ls-dr10-resid will instead return cutouts for the model and residual images, respectively. For more options, see the Legacy Surveys page on Obtaining Images and the Legacy Surveys Viewer Tips and Tricks.

DR9:
JPEG:   https://www.legacysurvey.org/viewer/cutout.jpg?ra=199.1111&dec=17.700&layer=ls-dr9&pixscale=1.00&bands=grz

FITS:   https://www.legacysurvey.org/viewer/cutout.fits?ra=199.1111&dec=17.700&layer=ls-dr9&pixscale=0.25

where "bands" is a string such as "grz","gz","g", etc. This will merge the northern (MzLS+BASS) and equatorial (DECam) images at the Dec=32.375 line. Replacing layer=ls-dr9 with layer=ls-dr9-model or layer=ls-dr9-resid will instead return cutouts for the model and residual images, respectively.

DR8:
JPEG:   http://legacysurvey.org/viewer/jpeg-cutout/?ra=190.1086&dec=1.2005&layer=dr8&pixscale=0.27&bands=grz

FITS:   http://legacysurvey.org/viewer/fits-cutout/?ra=190.1086&dec=1.2005&layer=dr8&pixscale=0.27&bands=grz

where "bands" is a string such as "grz","gz","g", etc. This will merge the northern (MzLS+BASS) and equatorial (DECam) images at the Dec=32.375 line. Replacing layer=dr8 with layer=dr8-model or layer=dr8-resid will instead return cutouts for the model and residual images, respectively.

The NSF’s NOIRLab Astro Data Archive access

The NSF’s NOIRLab Astro Data Archive portal can be used to retrieve raw, and calibrated Legacy Surveys images, as well as the Tractor catalogs. Use the Search tool in the Astro Data Archive.