The Large Synoptic Survey Telescope will survey about 20,000 square degrees of the sky to unprecedented depth and superb image quality. This is possible because of LSST's large effective optical throughput: the 8.4m aperture and 10 square degree field of view gives rise to an "etendue" of 300 sq.m sq.deg. The resulting survey to low surface brightness (29.5 AB magnitude/sq.deg in 5 filters) enables precision control of shear systematics, resolution of 50 source galaxies per sq.arcminute, and good color-redshifts. This database of shapes and redshifts for 3 billion galaxies can be analyzed in several independent tests of dark energy. Realistic constraints on dark energy, some of the other key science from these same imaging data, and the progress on the LSST project will be reviewed.

Refreshments at 3:30 p.m. in the Steward Observatory Lobby