Packed into this single image from Rubin Observatory are many different kinds of galaxies: spirals with delicate arms, smooth elliptical galaxies, distorted merging galaxies, and faint red galaxies from the distant universe. Only a relatively small number of bright stars from our own Milky Way appear in the foreground, leaving an unusually clear view of galaxies stretching far into the distance.

This image was captured with Rubin's 3.2-gigapixel LSST Camera—the largest digital camera in the world, mounted on the 8.4-meter Simonyi Survey Telescope. It features the well-known and well-studied region of sky known as the COSMOS field. It was created by stacking hundreds of individual observations and contains more than half a million galaxies and more than 50,000 stars.

The COSMOS field is especially valuable to astronomers because it looks away from the crowded plane of our Milky Way. With fewer nearby stars and clouds of dust blocking the view, telescopes can see enormous numbers of distant galaxies, many so far away that their light has traveled for billions of years before reaching Earth. Looking deeper into space also means looking farther back in time, allowing scientists to study galaxies at many different stages in the history of the universe.

Astronomers have studied COSMOS for more than two decades. Beginning with observations by the Hubble Space Telescope in 2003, researchers around the world have pointed many of the world's leading telescopes at this same area, observing it in wavelengths ranging from radio waves to X-rays. Because the field has been observed so extensively, it serves as an important reference point for testing new data, comparing measurements and combining information from many observatories.