C/2018 Y1
Not currently visible. Last report 2460 days ago at mag 31.0. Historic peak was mag 5.5. 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
31.0
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
531
Arc unknown
Last observation
2460d ago
Sun, 22 Dec 2019 23:45:35 GMT · COBS consensus
Perihelion
2019-02-02
1.300 au
Peak window
2019-01-30 → 2019-02-14
COBS peak mag 5.5 on 2019-02-11 · perihelion 2019-02-02. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.5
COBS / analyzed peak 2019-02-11
Catalog ingest
2d ago
Venator last wrote this row 2026-09-14 20:00:19 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
1.300 au
e
0.9900
i
160.00°
Ω
147.00°
ω
358.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
—
COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2018 Y1 (Iwamoto)
Informal: Iwamoto
C/2018 Y1 · 2026-09-14 18:27:59 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:59 UTC → current
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1–40 of 82
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.