Two independent ground-based observations on November 16 and 17, 2025 have provided the first detailed post-perihelion documentation of jet morphology on 3I/ATLAS, the third confirmed interstellar object.
The images show multiple narrow jets, a pronounced anti-tail, and a long collimated dust tail, all captured as the object continues to fade after passing perihelion.
The November 16 dataset, recorded between 11:53 and 12:23 UTC by Satoru Murata using a 0.2 m Celestron EdgeHD 800 telescope in New Mexico, USA, consists of 24 exposures of 60 s. The composite image reveals several jets directed both toward and away from the Sun, with clear structure despite the object’s decreasing brightness.
On November 17 at 17:04 UTC, Francois Kugel captured a second sequence using a 0.4 m telescope in France, combining 22 exposures of 30 s. This independent image displays the same multi-directional jet features observed the previous day.
The similarity between the two composites indicates stable jet morphology over a period of at least 24 hours. For a small, active interstellar object, this level of structural consistency is notable, as rotational motion commonly produces visible variations in short-exposure observations.
3I/ATLAS live stream
The Virtual Telescope Project confirmed that its planned observation session of 3I/ATLAS, originally scheduled earlier in the week, was postponed due to cloud cover over the observing site. The team rescheduled the session for 04:15 UTC on November 19, 2025, providing one of the last opportunities for real-time monitoring of the object as it continues to fade after perihelion.
The event will use the project’s remotely operated instruments to track the comet’s motion and record its remaining activity.
Given the object’s rapid decline in brightness and increasing distance from the Sun, the livestream is expected to offer limited but still valuable visual data, especially for confirming whether the multi-directional jets seen on November 16–17 remain detectable at lower flux levels.
The session is open to the public through the Virtual Telescope Project’s online platform, providing live imagery and commentary as long as weather conditions permit.
3I/ATLAS was discovered on July 1, 2025 by the ATLAS survey. The object follows a hyperbolic trajectory and passed perihelion on October 29, at approximately 1.36 AU from the Sun.
As it moves outward, its decreasing brightness limits opportunities for detailed imaging with small and medium apertures, making the mid-November observations among the final high-quality ground-based datasets expected from amateur equipment.
Featured image: 3I/ATLAS on November 16, 2025. Credit: Satoru Murata