C/2018 A3
Not currently visible. Last report 2435 days ago at mag 27.6. Historic peak was mag 15.8. Typical backyard telescopes will not show it. HST, JWST, or an 8–10 m class telescope might recover it with a good ephemeris.
Right ascension
—
J2000
Declination
—
J2000
Estimated magnitude
27.6
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
54
Arc unknown
Last observation
2435d ago
Thu, 16 Jan 2020 20:38:23 GMT · COBS consensus
Perihelion
2019-01-08
3.300 au
Peak window
2019-01-05 → 2019-01-12
COBS peak mag 15.8 on 2019-01-09 · perihelion 2019-01-08. Window is those dates ±3 days — not a light-curve fit.
Historic peak
15.8
COBS / analyzed peak 2019-01-09
Catalog ingest
9h ago
Venator last wrote this row 2026-09-16 13:20:18 UTC
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.
q
3.300 au
e
0.9910
i
140.00°
Ω
194.00°
ω
86.60°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2018 A3 (ATLAS)
Informal: ATLAS
C/2018 A3 · 2026-09-14 18:27:59 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:59 UTC → current
CCD Observer · HIL04 · 32 reports · last 2435d ago
CCD Observer · MAS01 · 6 reports · last 2760d ago
CCD Observer · DEK01 · 5 reports · last 2452d ago
CCD Observer · WAR01 · 4 reports · last 2542d ago
CCD Observer · FRI02 · 4 reports · last 2771d ago
CCD Observer · SWA01 · 2 reports · last 2736d ago
CCD Observer · YOS02 · 2 reports · last 2846d ago
Visual Observer · SZA · 1 reports · last 2796d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.