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Venator

Early warning for newly discovered comets and unconfirmed objects.

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C/2021 G2

C/2021 G2 (ATLAS)

CometClass Ecatalogued
Northern hemisphere

Not visible to typical instruments. Current estimate mag 18.6. Historic peak was mag 15.8. Visual and most CCD amateur setups will not see it. Space telescopes or large ground telescopes are the remaining path.

Active comet in COBS

JSONCSV

Right ascension

01h 33m 39s

J2000

Declination

+27° 03′ 35″

J2000

Estimated magnitude

18.6

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

0

Arc unknown

Last observation

31h ago

Tue, 15 Sep 2026 18:43:11 GMT · COBS consensus

Perihelion

2024-09-09

4.980 au

Peak window

2024-05-15 → 2024-09-12

COBS peak mag 15.8 on 2024-05-18 · perihelion 2024-09-09. Window is those dates ±3 days — not a light-curve fit.

Historic peak

15.8

COBS / analyzed peak 2024-05-18

Catalog ingest

13m ago

Venator last wrote this row 2026-09-17 01:55:25 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

4.980 au

e

1.0000

i

48.50°

Ω

221.00°

ω

343.00°

a

-3800.000 au

MOID

—

H

—

H0 / n

9.6 / 1

NEO score

—

PHA score

—

RMS

—

Elongation

139°

Reporting sources

  • COBS comet list

    down

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

  • COBS orbits

    down

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

Name history

  • C/2021 G2 (ATLAS)

    Informal: ATLAS

    C/2021 G2 · 2026-09-13 22:21:23 UTC → current

Discoverers

  • ATLAS

    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.