The 10-year Legacy Survey of Space and Time (LSST) is Rubin Observatory’s flagship wide-field sky survey, designed to repeatedly image the southern sky for a decade and turn those repeated measurements into a time-lapse record of the changing universe. It will combine very wide coverage, rapid revisits, and deep imaging to study dark matter, dark energy, the Milky Way, transient events, and solar-system objects.
 
LSST will survey about 18,000 square degrees of the southern sky in six filters, revisiting the same regions roughly every few nights as part of the Wide Fast Deep program. The observing strategy is built around ~30-second exposures and a cadence that lets astronomers detect moving, brightening, or fading objects over time. Rubin’s camera is a 3.2-gigapixel system, and the survey is expected to generate enormous data volumes for public scientific use.
 
Rubin states four core science goals for LSST: probing dark energy and dark matter, inventorying the solar system, exploring the transient optical sky, and mapping the Milky Way. In practical terms, that means finding asteroids and other small bodies, tracking supernovae and variable stars, and measuring faint cosmic structure through techniques such as weak lensing. The survey is also intended to create a major public archive for broad research use.
 
The key idea is repetition: LSST is not about one spectacular image, but about comparing the same sky over and over to detect change. That makes it unusually powerful for time-domain astronomy, where the important signal is often motion or variability rather than a single snapshot. Over 10 years, it should produce a dataset large enough to reshape work in cosmology, Galactic astronomy, and planetary defence.
 
A simple way to think about LSST is as an astronomical surveillance and census system: it watches the sky continuously, catalogues what is there, and flags what changes. For a visually oriented overview of the observatory itself, a night image of Rubin Observatory is available.
 
References
(2026). See the Universe in Action. Vera C. Rubin Observatory. https://rubinobservatory.org/
 
(2026, 30 June). Action! NSF-DOE Vera C Rubin Observatory Begins Capturing the Greatest Cosmic Movie Ever Made. Vera C. Rubin Observatory. https://rubinobservatory.org/news/action-rubin-lsst-begins
 
(2026, 30 June). Vera C. Rubin Observatory. In Wikipedia: https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory