Legacy Survey - MzLS

The Mayall z-band Legacy Survey (MzLS) will cover ~5000 deg² in the z band to depth of z=23.0.

Current Status

The eigth data release (DR8) includes the entire MzLS footprint of ~5300 deg2 in the z band. DR8-north contains MzLS images taken between 19th November 2015 through 12th February 2018, and supersedes the previous MzLS release (DR6).


The observations are taken with MOSAIC on the Mayall telescope in three passes at each sky location. "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.

Single exposures reach 5-sigma point source depth of 23.04 (pass 1), 22.95 (pass 2), and 22.85 (pass 3).

Joining DR8-north & DR8-south

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.