C/2009 R1
Not currently visible. Last report 5918 days ago at mag 31.3. Historic peak was mag 4.6. 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
31.3
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
268
Arc unknown
Last observation
5918d ago
Sun, 04 Jul 2010 20:52:48 GMT · COBS consensus
Perihelion
2010-06-30
0.398 au
Peak window
2010-06-27 → 2010-07-03
COBS peak mag 4.6 on 2010-06-30 · perihelion 2010-06-30. Window is those dates ±3 days — not a light-curve fit.
Historic peak
4.6
COBS / analyzed peak 2010-06-30
Catalog ingest
11h 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
0.398 au
e
1.0000
i
76.80°
Ω
323.00°
ω
130.00°
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/2009 R1 (McNaught)
Informal: McNaught
C/2009 R1 · 2026-09-14 18:27:53 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:53 UTC → current
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Visual Observer · LEH · 15 reports · last 5927d ago
Visual Observer · WOL01 · 14 reports · last 5953d ago
Visual Observer · GON05 · 12 reports · last 5918d ago
Visual Observer · BIV · 12 reports · last 5928d ago
Visual Observer · AMO01 · 11 reports · last 5946d ago
Visual Observer · WYA · 11 reports · last 5965d ago
Visual Observer · HAH · 11 reports · last 5927d ago
Visual Observer · HOR03 · 11 reports · last 5933d ago
Visual Observer · LAB02 · 9 reports · last 5929d ago
Visual Observer · SCI · 8 reports · last 5930d ago
Visual Observer · YOS02 · 7 reports · last 5941d ago
Visual Observer · NAG04 · 7 reports · last 5936d ago
Visual Observer · PAR03 · 7 reports · last 5924d ago
Visual Observer · PAR · 7 reports · last 5924d ago
Visual Observer · MYS · 6 reports · last 5929d ago
Visual Observer · GUZ · 6 reports · last 5939d ago
CCD Observer · SHU · 6 reports · last 5936d ago
Visual Observer · SCH04 · 5 reports · last 5935d ago
Visual Observer · HOR02 · 5 reports · last 5925d ago
CCD Observer · YOS02 · 5 reports · last 5943d ago
Visual Observer · MOR03 · 5 reports · last 5932d ago
Visual Observer · HER02 · 4 reports · last 5941d ago
Visual Observer · CER01 · 4 reports · last 5929d ago
Visual Observer · KOU · 4 reports · last 5945d ago
Visual Observer · KAC02 · 4 reports · last 5929d ago
Visual Observer · SHA02 · 4 reports · last 5930d ago
Visual Observer · RES · 4 reports · last 5939d ago
Visual Observer · TSU02 · 4 reports · last 5941d ago
Visual Observer · PIL01 · 4 reports · last 5928d ago
Visual Observer · LOO01 · 3 reports · last 5940d ago
Visual Observer · ATA · 3 reports · last 5929d ago
Visual Observer · MAC08 · 3 reports · last 5929d ago
Visual Observer · SWI · 3 reports · last 5929d ago
Visual Observer · CSU · 3 reports · last 5943d ago
Visual Observer · DEK01 · 3 reports · last 5940d ago
Visual Observer · VOL · 3 reports · last 5941d ago
Visual Observer · KAM01 · 2 reports · last 5945d ago
1–40 of 68
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.