Using JWST’s NIRCam, a team led by SwRI discovered a very faint new moon of Uranus by combining ten 40-minute exposures taken over a six-hour span on 2 February 2025. Each image is a composite of three different data treatments to reveal atmosphere, rings and faint satellites simultaneously. The object, designated S/2025 U1, is visible across the sequence but was too faint for Voyager 2 to have detected in 1986. The discovery highlights advances in long-exposure imaging and data processing and offers inspiration to astrophotographers planning observations in May 2026.
Ten 40-Minute JWST Exposures Reveal an Ultra-Faint Uranian Moon Voyager 2 Missed
Credit: Getty Images / Allexxandar
The Artemis II launch has renewed public interest in space photography, and a recent re-examination of James Webb Space Telescope (JWST) data highlights just how powerful modern imaging can be. A team led by the Southwest Research Institute (SwRI) announced the discovery of an extremely faint new moon orbiting Uranus — a satellite so dim that NASA’s Voyager 2 missed it during its 1986 flyby.
How the Moon Was Detected
Researchers used JWST’s primary near-infrared camera, NIRCam, to capture ten 40-minute exposures of Uranus. All frames were recorded within a roughly six-hour window on 2 February 2025 (01:05–06:54 UT). The discovery relies on careful stacking and processing: each frame shown in the team’s video is a composite of three different treatments of the same data so that the planetary atmosphere, the faint rings and tiny satellites can be revealed simultaneously.
The newly identified satellite has been designated S/2025 U1. In the processed sequence it is circled to guide the eye; although extremely faint, it appears consistently across multiple frames and its motion relative to Uranus is clearly visible in the time series.
Why Voyager 2 Didn’t See It
Voyager 2 remains the only spacecraft to have visited Uranus in person, but its instruments and imaging techniques from the 1980s were less sensitive to tiny, low-reflectivity moons than modern telescopes. JWST benefits from a large mirror, very sensitive detectors and advanced image-processing methods that allow faint objects like S/2025 U1 to be pulled out of the background light of the planet and rings.
What This Means For Astronomy and Astrophotography
This find is a clear demonstration of how long exposures, infrared sensitivity and sophisticated data treatment extend the reach of planetary astronomy. For amateur and professional astrophotographers alike, it underlines the value of long integrations and careful post-processing when hunting faint targets. While the full moon may limit some observing this evening, May 2026 still promises many attractive celestial targets for photographers with the right equipment and technique.
Quick Facts: Instrument: JWST NIRCam | Exposures: 10 × 40 minutes | Observation Window: 02 Feb 2025, 01:05–06:54 UT | New Moon: S/2025 U1
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