As part of its initial test operations, the Rubin Observatoryhad its camera pointed at a region of the sky that, by chance, intersected with the path of 3I/ATLAS. On June 21, during what researchers described as “an act of cosmic serendipity,” Rubin’s powerful imaging system captured the interstellar object as it journeyed toward the Sun. Although the comet’s official discovery came later, these early snapshots have proven invaluable in confirming its interstellar nature and behavior.
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The comet’s identity was formally recognized by the International Astronomical Union’s Minor Planet Center on July 2, which confirmed that 3I/ATLAS originated from outside the solar system. Initial detection came from data collected by the Asteroid Terrestrial-impact Last Alert System (ATLAS) between June 25 and 29, and again on July 1. Around the same time, the Deep Random Survey telescope in Rio Hurtado, Chile, also observed the object.
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Rubin’s early observations were documented in a recent paper published onarXiv, which includes 49 total images of the comet. Some images were omitted from the analysis due to being captured during alignment calibration phases, which left them slightly out of focus. Nineteen images were acquired during deliberate operations and offered sharp views of 3I/ATLAS’s comet-like features, such as its coma and movement pattern.

These high-quality images are especially important because they were taken by a precision instrument during the comet’s earliest observable phase. They offer scientists a head start in understanding its composition, trajectory, and behavior as it speeds through our system. This kind of early data is rarely available for interstellar visitors, and Rubin’s imaging capability may open new avenues for studying such fleeting cosmic encounters.

https://www.msn.com/en-nz/news/other/world-s-most-powerful-telescope-just-spotted-a-visitor-from-another-star-system-10-days-before-anyone-else/ar-AA1JsokP?cvid=241681CE0FB64278BC8E783F46EB7F09&ocid=iehp&apiversion=v2&noservercache=1&domshim=1&renderwebcomponents=1&wcseo=1&batchservertelemetry=1&noservertelemetry=1

New telescope captures interstellar comet speeding through space in video

The NSF-DOE Vera C. Rubin Observatory in Chile recently captured rare footage of the visitor known as 3I/ATLAS — only the third interstellar object discovered. What’s more impressive: The observatory recorded the video a full 10 days before the comet was officially identified by NASA's Asteroid Terrestrial-impact Last Alert System.
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"While there's *nothing wrong* with thinking about whether some interstellar objects could be alien technology," said Jason Wright, a Penn State astronomy and astrophysics professor, on X, "3I/ATLAS has had its coma clearly detected since July 3. It's very clearly, *unambiguously*, a comet."

Scientists are especially excited about this discovery not just because of what it is, but because of how it was found. The Rubin Observatory, while still being tested, managed to catch the comet before anyone even knew to look. That bodes well for the future. Researchers estimate Rubin could find dozens more of these interlopers in the coming decade — possibly up to 50.

https://mashable.com/article/comet-3iatlas-interstellar-video