C/2000 W1
Not currently visible. Last report 9274 days ago at mag 35.8. Historic peak was mag 5.9. 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
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J2000
Declination
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J2000
Estimated magnitude
35.8
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
99
Arc unknown
Last observation
9274d ago
Thu, 26 Apr 2001 20:38:23 GMT · COBS consensus
Perihelion
2000-12-26
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Peak window
2000-12-22 → 2000-12-29
COBS peak mag 5.9 on 2000-12-25 · perihelion 2000-12-26. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.9
COBS / analyzed peak 2000-12-25
Catalog ingest
11h ago
Venator last wrote this row 2026-09-16 13:20:17 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
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e
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i
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Ω
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ω
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a
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MOID
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H
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H0 / n
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NEO score
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PHA score
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RMS
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Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2000 W1 (Utsonomiya-Jones)
Informal: Utsonomiya-Jones
C/2000 W1 · 2026-09-14 18:27:56 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:56 UTC → current
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Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.