C/1999 S3
Not currently visible. Last report 9643 days ago at mag 32.8. Historic peak was mag 13.0. 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
32.8
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
224
Arc unknown
Last observation
9643d ago
Sun, 23 Apr 2000 18:57:35 GMT · COBS consensus
Perihelion
1999-11-23
1.870 au
Peak window
1999-10-12 → 1999-11-26
COBS peak mag 13.0 on 1999-10-15 · perihelion 1999-11-23. Window is those dates ±3 days — not a light-curve fit.
Historic peak
13.0
COBS / analyzed peak 1999-10-15
Catalog ingest
14h ago
Venator last wrote this row 2026-09-17 13:20:21 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
1.870 au
e
0.9000
i
70.70°
Ω
12.00°
ω
44.00°
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/1999 S3 (LINEAR)
Informal: LINEAR
C/1999 S3 · 2026-09-14 18:27:54 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:54 UTC → current
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Seiichi Yoshida and KenIchi Kadota
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Visual Observer · BIV · 20 reports · last 9773d ago
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Visual Observer · MEY · 10 reports · last 9752d ago
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CCD Observer · LIG · 8 reports · last 9753d ago
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Visual Observer · MOR03 · 6 reports · last 9777d ago
CCD Observer · NAK01 · 5 reports · last 9786d ago
Visual Observer · YOS04 · 5 reports · last 9766d ago
Visual Observer · HAS02 · 5 reports · last 9731d ago
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Visual Observer · PLE01 · 3 reports · last 9790d ago
Visual Observer · YOS02 · 3 reports · last 9778d ago
Visual Observer · DRA02 · 3 reports · last 9790d ago
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Visual Observer · MAR02 · 2 reports · last 9782d ago
CCD Observer · SUZ02 · 2 reports · last 9806d ago
Visual Observer · KUT · 2 reports · last 9845d ago
Visual Observer · NAG08 · 2 reports · last 9791d ago
Visual Observer · PER01 · 1 reports · last 9835d ago
Visual Observer · GRA04 · 1 reports · last 9791d ago
Visual Observer · OKS · 1 reports · last 9836d ago
Visual Observer · SAN04 · 1 reports · last 9782d ago
CCD Observer · HOR02 · 1 reports · last 9643d ago
Visual Observer · MIY01 · 1 reports · last 9822d ago
Visual Observer · RAY · 1 reports · last 9841d ago
CCD Observer · ROQ · 1 reports · last 9852d ago
Visual Observer · MOR09 · 1 reports · last 9812d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.