C/1987 U3
Not currently visible. Last report 14059 days ago at mag 35.9. Historic peak was mag 9.6. 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
35.9
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
281
Arc unknown
Last observation
14059d ago
Tue, 10 May 1988 22:19:11 GMT · COBS consensus
Perihelion
1987-12-25
0.853 au
Peak window
1987-12-22 → 1987-12-28
COBS peak mag 9.6 on 1987-12-25 · perihelion 1987-12-25. Window is those dates ±3 days — not a light-curve fit.
Historic peak
9.6
COBS / analyzed peak 1987-12-25
Catalog ingest
13h ago
Venator last wrote this row 2026-11-06 14:20:20 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
0.853 au
e
0.9980
i
97.00°
Ω
261.00°
ω
17.40°
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/1987 U3 (McNaught)
Informal: McNaught
C/1987 U3 · 2026-09-14 18:27:57 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:57 UTC → current
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1–40 of 56
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.