Comet C/2025 R3 PanSTARRS: How to See It in April 2026

A brand-new comet is on its way into the inner Solar System — C/2025 R3 (PanSTARRS). Discovered in September 2025, it will make its closest approach to the Sun and Earth in late April 2026, flying between the orbits of Venus and Mercury. The comet is expected to brighten to about magnitude 8, making it a fine binocular target. However, some models suggest it could reach magnitude 3, which would make it visible to the naked eye under dark skies! Track Comet C/2025 R3 easily with the free Sky Tonight app — just type its name and see where it will appear in your sky.

Contents

• What is Comet C/2025 R3?
• Comet C/2025 R3: Orbit and trajectory
• When and where to see Comet C/2025 R3
• Comet C/2025 R3: Discovery
• Why is the comet called C/2025 R3 (PanSTARRS)?
• Scientific significance
• Comet C/2025 R3: Summary

What is Comet C/2025 R3?

• Type: long-period comet
• Orbital period: unknown
• Perihelion: April 20, 2026 (~0.51 AU)
• Closest approach to Earth: April 27, 2026 (~0.53 AU)
• Predicted peak brightness: most probably mag 8; possibly up to mag 3
• Best visible from: Northern Hemisphere

C/2025 R3 (PanSTARRS) is a newly discovered long-period comet, which means it spends most of its time far beyond the planets, in the distant reaches of the Solar System. Objects like this can take tens of thousands or even millions of years to return, and some visit us only once. You can learn more about different types of comets in our dedicated article.

Comet C/2025 R3: Orbit and trajectory

The orbit of Comet R3 is unusual. It is tilted by about 125° relative to the plane of the planets, which means it approaches the Sun on a retrograde orbit (moving in the opposite direction to the planets). Such steeply inclined paths are typical for comets that come from the Oort Cloud, a vast reservoir of icy bodies surrounding the Solar System.

Another intriguing aspect is the comet’s future. Preliminary calculations show its path may be so elongated that it doesn’t form a closed loop around the Sun. If confirmed, this would make the comet’s orbit hyperbolic, meaning it will swing past the Sun once and then head back out into interstellar space. In that case, April 2026 could be the only time in history when humans get to see C/2025 R3. Even if later refinements show the orbit is still bound, the period would likely be so long that no one alive today would ever see it return.

When and where to see Comet C/2025 R3

Most probably, C/2025 R3 will reach magnitude 8 — too faint for the naked eye, but potentially visible in binoculars under dark skies. However, there’s a small chance it could shine as bright as magnitude 3 due to the effect of forward scattering, becoming faintly visible to the naked eye. The best chance to see it will be in late April to early May 2026, low in the twilight sky. Its visibility will differ by hemisphere: observers in the Northern Hemisphere may catch it in morning skies, while those in the Southern Hemisphere will see it in the evening skies in early May.

In April 2026, Comet C/2025 R3 will pass through the constellations Pegasus, Pisces, Cetus, and Taurus. At perihelion on April 20, it will be positioned in the constellation Pisces. At its closest approach to Earth on April 27, the comet will be in Cetus.

When preparing to observe a comet, the Moon is an important factor to consider, as its brightness can wash out faint celestial objects. Even if the comet reaches magnitude 8, its diffuse coma and tail might be hard to see against a bright sky. That’s why planning around the Moon’s cycle is crucial. Here’s how it looks for spring 2026:

• April 17, 2026 – New Moon: the best window for comet hunting, since the sky will be as dark as possible.
• April 24, 2026 – First Quarter: the half-illuminated Moon will remain in the sky for much of the evening, adding background light and making the comet harder to spot.
• May 1, 2026 – Full Moon: the worst time for observation — the Moon’s glare dominates the sky all night, overwhelming faint details of the comet.
• May 8, 2026 – Last Quarter: conditions begin to improve again, with the Moon rising later at night and leaving the early hours darker.

To maximize your chances, aim for the week around the New Moon in mid-April, or the early mornings in late April, when the Moon has already set, and the sky is darker.

Comet C/2025 R3: Discovery

The comet was discovered on September 8, 2025, by the Pan-STARRS survey telescope in Hawaii. At the time, it appeared only as a faint 19th-magnitude speck — far too dim for the unaided eye or even amateur telescopes and visible only with sensitive CCD detectors. Follow-up observations confirmed its motion against background stars, and soon after, orbit calculations were published through the Minor Planet Center (MPC), establishing it as a new cometary body.

Pan-STARRS stands for Panoramic Survey Telescope & Rapid Response System — an automated sky survey project in Hawaii that scans the heavens for asteroids, comets, and other transient objects. The program has become one of the world’s most prolific discoverers of new comets, including C/2025 R3.

Why is the comet called C/2025 R3 (PanSTARRS)?

The official designation C/2025 R3 follows the standard comet naming convention:

• C/ — a non-periodic comet, usually on a long-period or hyperbolic orbit.
• 2025 — the year of discovery.
• R — indicates discovery in the first half of September (each half-month is assigned a letter from A to Y, skipping I).
• 3 — it was the third comet discovered in that half-month.

The suffix PanSTARRS is attached to the name to credit the survey project that made the discovery.

Scientific significance

Long-period comets like C/2025 R3 are pristine leftovers from the early Solar System, likely formed in the cold, distant Oort Cloud. Studying their gases and dust provides insights into planetary formation. Because R3 is on a retrograde, steep orbit, its dynamics can also inform models of how Oort Cloud objects are perturbed into the inner Solar System.

Comet C/2025 R3: Summary

Comet C/2025 R3 PanSTARRS is a fresh cosmic traveler from the farthest reaches of our Solar System. On April 20, 2026, it will make its closest approach to the Sun, when it’s expected to brighten to binocular range. Some forecasts even allow it to reach magnitude 3, making it faintly visible to the naked eye. Whatever its final brightness, this rare visitor is well worth your attention! Use the Sky Tonight app to find out the comet’s exact position in your sky and track its path through the Solar System. And while you wait for April 2026, check out the list of upcoming comets for 2025 — a few of them look especially promising!