C/1999 H1
Not currently visible. Last report 9750 days ago at mag 32.5. Historic peak was mag 6.7. 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
32.5
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
1362
Arc unknown
Last observation
9750d ago
Thu, 06 Jan 2000 17:31:12 GMT · COBS consensus
Perihelion
1999-06-27
0.720 au
Peak window
1999-06-24 → 1999-06-30
COBS peak mag 6.7 on 1999-06-27 · perihelion 1999-06-27. Window is those dates ±3 days — not a light-curve fit.
Historic peak
6.7
COBS / analyzed peak 1999-06-27
Catalog ingest
9h ago
Venator last wrote this row 2026-09-16 13:20:16 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
0.720 au
e
1.0000
i
149.00°
Ω
163.00°
ω
40.90°
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 H1 (Lee)
Informal: Lee
C/1999 H1 · 2026-09-14 18:27:54 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:54 UTC → current
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1–40 of 154
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.