Legacy Survey - Overview

The Legacy Surveys 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 eigth data release (DR8) is the first release to contain data over the entire footprint of the DESI survey, including data from MzLS (z band) and BASS (g & r bands) surveys (DR8-north}), and data from DECaLS (g, r, & z bands; DR8-south). The footprint of DR8 covers approximately 13,000 deg2 with 3 passes in all three optical filters (g, r, z), and over 19,000 deg2 with at least one pass in all three filters.

A sky map of the full imaging survey coverage is included below, color-coded by the depth in the z-band filter, and shown in an equatorial projection. The solid grey line traces the Galactic plane. (Figure credit: Dustin Lang).

Visit the Data Access page for instructions to access the database, retrieve Legacy Survey images, and catalogs.