First observed · Sep 8, 2025 · PanSTARRS Survey, Haleakalā, Hawaii

Comet C/2025 R3
PanSTARRS

A once-in-a-lifetime hyperbolic visitor from the Oort Cloud. Currently approaching perihelion — visible in the pre-dawn sky. It will never return.

Closest to Sun
Apr 19
0.499 AU · Perihelion
Closest to Earth
Apr 26
73.2M km · 0.489 AU
Current magnitude
~4.6
JPL estimate
Peak brightness
mag 3.5
Optimistic: mag 0
Image: AI-generated illustration for editorial use
Real-time sky tracker
Current position in the sky
Ephemeris data from NASA/JPL Horizons — the same system used by professional observatories worldwide. Updates live to your location.
C/2025 R3 (PanSTARRS) — Locating…
--:--:-- UTC
⚑
Detecting…
Right Ascension
23h 48m
ICRF J2000
Declination
+18° 24′
ICRF J2000
Azimuth
—
from North
Elevation
—
above horizon
Magnitude
~4.6
visual
⚠ The comet is currently below your horizon. Best pre-dawn window: ~90 min before local sunrise.
Comet C/2025 R3
Stars
Jupiter (ref)
Great Square of Pegasus
Data: NASA/JPL Horizons API IAU ICRF J2000 GPS / IP Geolocation Nominatim Geocoding
Solar system simulation
Orbital trajectory
Live 2D orrery showing comet R3's position relative to the planets — data from NASA/JPL Horizons vector ephemeris, heliocentric ecliptic J2000 frame.
Orrery
Sep 2025 Aug 2026
C/2025 R3 PanSTARRS
Earth
Mars
Jupiter
◆ Perihelion marker
◆ Earth closest approach
Simulation range: Sep 1, 2025 → Aug 1, 2026 Drag the timeline slider or press Play to animate
Initializing…
NASA/JPL Horizons VECTORS ephemeris Ecliptic J2000 Heliocentric
Orbital approach
Timeline through the inner solar system
Key milestones from discovery through permanent solar system exit.
Sep 8, 2025
Discovery
Detected by PanSTARRS 1.8-m at Haleakalā, Hawaii at magnitude ~20. Faint diffuse coma, no tail. 3.60 AU from the Sun.
Mar 20, 2026
Binocular visibility
Visible in 10×50 binoculars. Ion tail begins forming. Brightness rising rapidly from magnitude ~17 in January.
Apr 7, 2026
Maximum elongation
33° from the Sun — ideal Northern Hemisphere window. Ion tail exceeds 7° on April 8.
Apr 11, 2026
Naked-eye confirmed
First naked-eye reports at estimated magnitude 5.1. Visible near the Great Square of Pegasus.
Milestone
Apr 18, 2026 — Today
Conjunction with NGC 7814
Passes ~2° from NGC 7814. New moon ensures optimal dark skies. Magnitude ~4.6.
Now
Apr 19, 2026
Perihelion
Closest to the Sun at 0.499 AU. Survival not guaranteed. Peak brightness window opens.
Apr 25–26, 2026
Solar conjunction & Earth closest approach
Solar conjunction Apr 25. Earth closest approach Apr 26 at 73.2M km. Forward scattering may boost brightness.
May 2026 onward
Southern Hemisphere & permanent exit
Best views shift south. R3 then exits the solar system on its hyperbolic trajectory. No return — ever.
Observing guide
How to see comet R3
From naked eye to astrophotography — your complete guide to finding C/2025 R3.
Equipment
Entry level
Naked eye
Possible at magnitude ~4.6 but appears as a faint fuzzy patch. Dark skies essential.
Currently marginal
Recommended
10×50 binoculars
The sweet spot. Wide field puts comet and tail in frame. Binocular-visible since March 20.
Best choice
Advanced
Telescope + camera
4–8" scope on tracking mount reveals dual ion tail. ISO 1600–3200, 15–30s exposures.
Astrophotography
Finder chart
Eastern pre-dawn sky · ~90 min before sunrise
North up · field ~25°
Best viewing dates
Conditions checklist

Do this

Go out at least 90 min before sunrise
Allow 20–30 min dark adaptation — red light only
Find a clear, flat eastern horizon
Use Great Square of Pegasus as your anchor

Avoid this

Going out too late — twilight washes it out fast
Light-polluted urban skies
High humidity or mist near the horizon
Waiting past April 20 if in Northern Hemisphere
Step-by-step plan
1

Check weather and moon phase

New moon was April 17 — currently ideal. This dark-sky window lasts only a few more days.

2

Find sunrise time, set an alarm

Look up local sunrise and subtract 90–100 minutes. Use the tracker above for your local data.

3

Get to a dark site, let eyes adapt

Drive away from streetlights. After 20 minutes your rod cells are fully dark-adapted.

4

Locate the Great Square of Pegasus

Face east. Look for four moderately bright stars in a large square, 10–20° above the horizon.

5

Sweep binoculars inside the square

Look for a fuzzy greenish patch with a faint elongated tail pointing away from the horizon.

Key step
6

Photograph if you can

Tripod, f/2.8–f/4, ISO 1600–3200, 10–30s. Stack 20+ frames in DeepSkyStacker or Siril.

Pro tips
◆

Use averted vision

Don’t look directly at the comet. Peripheral rods are far more sensitive to faint light.

◆

Dress for the cold

Pre-dawn hours are always colder than expected. Layer up and bring something warm to sit on.

◆

Forward scattering boost

After perihelion, forward scattering may dramatically boost brightness near solar conjunction.

◆

Southern hemisphere: wait for May

Philippines, Australia, South Africa — your window opens in late April into May.

◆

This is a one-time event

C/2025 R3 is on a hyperbolic orbit. After this pass it will be permanently ejected from the solar system.

◆

Use a sky app

SkySafari, Stellarium, or Star Walk 2 show R3’s precise nightly position from JPL Horizons data.

Updates
Latest news & observations
Recent reporting and community observations from around the world.
Today, Apr 18: Ideal dark-sky window following yesterday’s new moon. Best morning to observe before perihelion tomorrow. Look 90 min before sunrise in Pegasus.
APOD · NASA
Comet R3 is brightening rapidly — will it survive?
Already sporting a 10° ion tail photographed above Bietschhorn, Switzerland. Perihelion and Earth closest approach arrive within days.
Apr 12, 2026
APOD · NASA
The long wispy tail of comet R3 PanSTARRS
An impressive ion tail from a nucleus likely just a few km across, powered by solar heating and driven by the solar wind.
Apr 14, 2026
EarthSky
Comet R3 spotted with naked eye at magnitude 5.1
Community photos from India, Poland, Arizona and Italy show a greenish coma and narrow ion tail with filamentary structure.
Apr 11–13, 2026
Star Walk
Two distinct structures in R3’s ion tail
One ray-like stream at hundreds of km/s; one irregular and uneven. Optimistic forecast now includes magnitude 0.
Apr 10, 2026
Space.com
Why I’m hunting for comet PanSTARRS before it’s too late
Key viewing window is Apr 10–20. After perihelion the comet sinks into solar glare for Northern Hemisphere observers.
Apr 9, 2026
Wikipedia / JPL
Hyperbolic orbit confirms one-time solar system visitor
Orbital analysis confirms C/2025 R3 is on a hyperbolic trajectory from the Oort Cloud. It will be ejected after perihelion.
Discovery analysis
Reference data
Observational & physical data
Known parameters as of April 18, 2026.

Orbital parameters

Orbit typeHyperbolic (Oort Cloud)
Perihelion distance0.499 AU · 74.6M km
Perihelion dateApr 19, 2026
Earth closest approach0.489 AU · 73.2M km
Closest dateApr 26, 2026
Return periodNone — solar system exit

Brightness & visibility

Discovery magnitude~20
Current magnitude~4.6 (Apr 18)
Predicted peakmag 3.5 (baseline)
Optimistic peakmag 0
Naked-eye threshold~mag 4.0
Best tool10×50 binoculars

Physical properties

CompositionDirty ice & dust
Nucleus sizeA few km across
Ion tail (Apr 8)≥ 7° of sky
Tail structureDual — ray + irregular
Coma colorGreenish (C₂ emission)
Discovery telescopePanSTARRS 1.8-m, Haleakalā

Viewing guide

ConstellationPegasus
AsterismGreat Square of Pegasus
Best time90 min before sunrise
DirectionLow eastern horizon
N. HemisphereNow → Apr 20
S. HemisphereLate Apr → May 2026