Legacy Survey - Overview

The Legacy Survey will cover 14,000 square degrees of the extragalactic sky, and yield high-quality optical and near-infrared photometric catalogs. The sky coverage is approximately bounded by -18° < δ < +84° in celestial coordinates and |b| > 18° in Galactic coordinates. Resulting images, models, and catalogs will enhance current and future wide area surveys such as SDSS/BOSS/eBOSS and DESI.

The Legacy Survey data products and database are accessible via the NOAO Data Lab as described here. See the Legacy Survey team page for a complete description of the survey and data files.

The Legacy Survey is a combination of the DECam Legacy Survey (DECaLS) using the Dark Energy Camera on the Blanco 4m telescope, the Mayall z-band Legacy Survey (MzLS) using the MOSAIC instrument on the Mayall 4m telescope, and the Beijing-Arizona Sky Survey (BASS) using the 90Prime instrument at the Steward Observatory Bok telescope.

Legacy Survey
SurveyTelescopeBandArea
DECaLSBlancog, r, z9500 sq. deg
MzLSMayallz5000 sq. deg
BASSBokg, r5000 sq. deg
AllWISEWISEW1, W2, W3, W414000 sq. deg

Current status

The fifth data release (DR5 ) includes a portion of DECaLS, covering a disjoint footprint with 7400 deg² in g-band, 8000 deg² in r-band and 10200 deg² in z-band, of which 6800 deg² has been observed in all three optical filters.

The fourth data release (DR4) supplements DR5, and includes for the first time data from MzLS (z band) and BASS (g & r bands). The footprint of DR4 covers ~3600 deg2.

For comparison, the third data release (DR3) included an earlier version of DECaLS with 4300 deg² in g-band, 4600 deg² in r-band, 8100 deg² in z-band, and 4200 deg² in all three optical filters. DR5 supersedes DR3.

In order to obtain the full coverage of the Legacy Survey, one needs to combine both DR5 and DR4. Visit the Data Access page to retrieve Legacy Survey images, and catalogs.