C/1999 U1
Not currently visible. Last report 9781 days ago at mag 31.7. Historic peak was mag 15.9. 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
31.7
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
10
Arc unknown
Last observation
9781d ago
Fri, 28 Jan 2000 11:31:12 GMT · COBS consensus
Perihelion
1998-08-20
4.160 au
Peak window
1998-08-17 → 1998-09-14
COBS peak mag 15.9 on 1998-09-11 · perihelion 1998-08-20. Window is those dates ±3 days — not a light-curve fit.
Historic peak
15.9
COBS / analyzed peak 1998-09-11
Catalog ingest
15h ago
Venator last wrote this row 2026-11-07 14:20:17 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
4.160 au
e
0.9980
i
106.00°
Ω
58.00°
ω
291.00°
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/1999 U1 (Ferris)
Informal: Ferris
C/1999 U1 · 2026-09-14 18:27:57 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:57 UTC → current
CCD Observer · NAK01 · 7 reports · last 9781d ago
CCD Observer · YOS04 · 3 reports · last 9857d ago
Seiichi Yoshida and KenIchi Kadota
CCD Observer · YOS05 · 3 reports · last 9857d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.