The Dark Energy Camera Legacy Survey (DECaLS) will cover ~9500 deg² in the g, r, z bands to depths of g=24.7, r=23.9, z=23.0. Infrared WISE data are also extracted at the location of the DECaLS sources.
The eighth data release (DR8) includes the full footprint of DECaLS in all three optical filters (DR8-south).
Images from DECaLS g, r, z-band observations (NOAO survey program 2014B-0404) are included from 9th August 2014 through 7th March 2019. DR8 also includes DECam data from a range of non-DECaLS surveys, including observations that were conducted from 1st September 2013 to 7th March 2019. A large portion of these non-DECaLS observations were taken by the Dark Energy Survey team. DR8 supersedes DR7 and previous DECaLS releases.
The observations are taken with DECam on the 4-meter Blanco telescope in three passes at each sky location, and in each filter (g, r, z). "Pass 1" is observed in photometric, good-seeing conditions. "Pass 2" and "Pass 3" are observed in progressively worse conditions. This strategy was adopted to ensure a photometric solution across the full survey area. The observing time is adjusted as a function of sky brightness and transparency.
Unique area is resolved by including the BASS and MzLS images (from DR8-north) if they are both at Declination > 32.375° and north of the Galactic Plane. Otherwise, the DECam images (from DR8-south) are used.