C/1998 H1
Not currently visible. Last report 10259 days ago at mag 35.5. Historic peak was mag 10.0. 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
35.5
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
159
Arc unknown
Last observation
10259d ago
Sat, 15 Aug 1998 19:40:48 GMT · COBS consensus
Perihelion
1998-04-04
1.480 au
Peak window
1998-04-01 → 1998-04-29
COBS peak mag 10.0 on 1998-04-26 · perihelion 1998-04-04. Window is those dates ±3 days — not a light-curve fit.
Historic peak
10.0
COBS / analyzed peak 1998-04-26
Catalog ingest
2d ago
Venator last wrote this row 2026-09-14 20:00:16 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
1.480 au
e
0.9970
i
104.00°
Ω
222.00°
ω
1.21°
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/1998 H1 (Stonehouse)
Informal: Stonehouse
C/1998 H1 · 2026-09-14 18:27:54 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:54 UTC → current
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Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.