The NSF–DOE Vera C. Rubin Observatory, perched high in the Chilean Andes, has released its Early Data Preview 2, a deep-field image assembled using the 3.2-gigapixel LSST Camera, the largest digital imaging device ever built for astronomical use. The image targets the well-studied COSMOS field, located in the constellation Sextans, and stacks together hundreds of individual exposures captured during the observatory’s commissioning phase between mid-2025 and early 2026.
Scale of the Survey
The resulting composite catalogues more than 500,000 distant galaxies alongside some 50,000 foreground stars from our own Milky Way, all within a single deep-field exposure — an extraordinary density of cosmic information captured in one coordinated observation. The broader Early Data Preview 2 release extends well beyond this single field, spanning a stacked survey region of approximately 3,000 square degrees, equivalent to roughly one-sixth of the entire southern celestial hemisphere.
A Ten-Year Cosmic Time-Lapse
This release represents only the opening phase of the observatory’s flagship scientific programme, the ten-year Legacy Survey of Space and Time. Over the coming decade, the Rubin Observatory will repeatedly re-image the entire southern sky every few nights, effectively producing a continuous time-lapse movie of the cosmos. That cadence is specifically designed to catch transient astronomical phenomena — supernovae, near-Earth asteroids, and other short-lived events — as they happen, while simultaneously building up the kind of deep, wide-field data needed to map the large-scale distribution of dark matter and to chart the ongoing expansion of the universe with unprecedented statistical precision.
For the astronomical community, the sheer scale of a single COSMOS field observation — half a million galaxies captured in one shot — offers an early indication of the data volumes the Legacy Survey will eventually generate, and of the discovery potential embedded in a telescope built explicitly to observe not just where things are in the sky, but how the sky changes over time.
– P Sai Chaitanya
