C/2011 C1
Not currently visible. Last report 5467 days ago at mag 38.4. Historic peak was mag 15.1. 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
38.4
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
166
Arc unknown
Last observation
5467d ago
Fri, 18 Nov 2011 21:07:11 GMT · COBS consensus
Perihelion
2011-04-19
0.899 au
Peak window
2011-04-07 → 2011-04-22
COBS peak mag 15.1 on 2011-04-10 · perihelion 2011-04-19. Window is those dates ±3 days — not a light-curve fit.
Historic peak
15.1
COBS / analyzed peak 2011-04-10
Catalog ingest
13h ago
Venator last wrote this row 2026-11-06 14:20:18 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
0.899 au
e
0.9990
i
16.20°
Ω
190.00°
ω
86.70°
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/2011 C1 (McNaught)
Informal: McNaught
C/2011 C1 · 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.