MEGA (Microlensing Exploration of the Galaxy and Andromeda) surveyed a roughly 1 deg2 field in central M31 where the magnitude and variation of microlensing optical depth is suspected to be greatest. These observations were concentrated in 1999- 2003, but with extended coverage spanning 1997-2007 (continuing now at sparse cadence). The imaging observations were performed primarily on the 2.5-meter Isaac Newton Telescope (INT), the Kitt Peak National Observatory (KPNO) 4-meter and MDM Observatory 2.4-meter and 1.3-meter telescopes. The current work signifies our merging of these four datasets into a single time sequence.