comets.venator.space

Venator

Early warning for newly discovered comets and unconfirmed objects.

Back to Contributors

C/2025 J1

C/2025 J1 (Borisov)

CometClass Ecatalogued
Southern hemisphere

Difficult — CCD / large telescope. Around mag 17.8. A large amateur CCD or a professional telescope is required.

Active comet in COBS

JSONCSV

Right ascension

18h 25m 23s

J2000

Declination

−36° 18′ 43″

J2000

Estimated magnitude

17.8

CCD / citizen telescope · COBS consensus

Confidence

33

Class E · priority 66

Observations

101

Arc unknown

Last observation

11d ago

Sun, 06 Sep 2026 02:23:59 GMT · COBS consensus

Perihelion

2026-06-11

3.580 au

Peak window

2026-01-31 → 2026-06-14

COBS peak mag 17.4 on 2026-02-03 · perihelion 2026-06-11. Window is those dates ±3 days — not a light-curve fit.

Historic peak

17.4

COBS / analyzed peak 2026-02-03

Catalog ingest

17m ago

Venator last wrote this row 2026-09-17 01:00:04 UTC

Light curve

Brightness over time (V mag)

Gold = reported observations. Steel dashed family = ensemble (nominal / outburst / fade / disruption).

Tail length

Converted to degrees from COBS (d / arcmin / arcsec). Empty until analysis has pulled the archive.

Ensemble is a first-pass H0/n photometric model plus observed samples — not a trained ML forecast yet. The background analyzer walks the catalog one object at a time so COBS is not flooded. Disruption track rises after perihelion to stand in for solar-wind stripping.

Orbital elements

q

3.580 au

e

0.9980

i

95.40°

Ω

274.00°

ω

167.00°

a

1880.000 au

MOID

—

H

—

H0 / n

13.1 / 1

NEO score

—

PHA score

—

RMS

—

Elongation

101°

Reporting sources

  • COBS comet list

    ok

    Comet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).

  • COBS orbits

    ok

    Osculating elements and photometric parameters (H0, n) for active comets.

Name history

  • C/2025 J1 (Borisov)

    Informal: Borisov

    C/2025 J1 · 2026-09-13 22:21:23 UTC → current

Discoverers

  • Borisov

    Discoverer · parsed-name · 2026-09-13 22:21:23 UTC → current

Contributors

Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.