C/2025 R2 (SWAN) — The Green Visitor
Captured with: Seestar S50 Smart Telescope
Perihelion (closest to Sun): ~12 September 2025 (at ~0.5 AU) Wikipedia+1
Nearest approach to Earth: ~20 October 2025 at ~0.26 AU (~39 million km) TheSkyLive+1
Orbit period (estimated): Tens of thousands of years (long-period) EarthSky+1
This one looks like a streak in the photo, because the photo is a composite of many individual 10 second shots. The comet moved slowly during these shots, so appears as a streak.
Originating far beyond the familiar inner Solar System, C/2025 R2 (SWAN) is a glowing iceberg of ice, dust and ancient frozen gases now venturing through our neighbourhood. Discovered on 11 September 2025 by Vladimir Bezugly via the SOHO/SWAN instrument. Wikipedia+1
Through the Seestar S50, you should see a vivid greenish coma (the nebulous head of the comet) and a faint tail stretching ~2-3 degrees across the sky — that’s about 4-6 times the diameter of the full Moon. EarthSky+1
Since comets are unpredictable, this one may brighten further or fade — but at its best, from a dark sky you might glimpse it with the naked eye (especially near peak), and binoculars will certainly help. Space+1
This green visitor is a reminder: cosmic time is slow, icy objects from the deep freeze wander in only occasionally, and when they do we get a chance at a fleeting spectacle.