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C/2020 R4

C/2020 R4 (ATLAS)

CometClass Ecatalogued
Unknown

Not visible to typical instruments. Current estimate mag 31.8. Historic peak was mag 7.7. Visual and most CCD amateur setups will not see it. Space telescopes or large ground telescopes are the remaining path.

Active comet in COBS

Right ascension

J2000

Declination

J2000

Estimated magnitude

31.8

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

302

Arc unknown

Last observation

5d ago

Fri, 11 Sep 2026 23:45:36 GMT · COBS consensus

Perihelion

2021-03-02

1.020 au

Peak window

2021-02-27 → 2021-04-23

COBS peak mag 7.7 on 2021-04-20 · perihelion 2021-03-02. Window is those dates ±3 days — not a light-curve fit.

Historic peak

7.7

COBS / analyzed peak 2021-04-20

Catalog ingest

14h ago

Venator last wrote this row 2026-09-16 13:20:18 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

1.020 au

e

0.9890

i

164.00°

Ω

323.00°

ω

46.50°

a

MOID

H

H0 / n

NEO score

PHA score

RMS

Elongation

Reporting sources

  • COBS comet list

    ok

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

Name history

  • C/2020 R4 (ATLAS)

    Informal: ATLAS

    C/2020 R4 · 2026-09-14 18:28:00 UTC → current

Discoverers

  • ATLAS

    Discoverer · parsed-name · 2026-09-14 18:28:00 UTC → current

Contributors

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