C/2015 P3
Not currently visible. Last report 4024 days ago at mag 36.9. Historic peak was mag 14.1. 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
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J2000
Declination
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J2000
Estimated magnitude
36.9
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
16
Arc unknown
Last observation
4024d ago
Fri, 11 Sep 2015 10:47:59 GMT · COBS consensus
Perihelion
2015-07-24
0.732 au
Peak window
2015-07-21 → 2015-08-03
COBS peak mag 14.1 on 2015-07-31 · perihelion 2015-07-24. Window is those dates ±3 days — not a light-curve fit.
Historic peak
14.1
COBS / analyzed peak 2015-07-31
Catalog ingest
12h ago
Venator last wrote this row 2026-09-16 13:20:17 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.
No tail measures stored yet for this object.
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
0.732 au
e
0.9970
i
58.10°
Ω
88.30°
ω
133.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2015 P3 (SWAN)
Informal: SWAN
C/2015 P3 · 2026-09-14 18:27:57 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:57 UTC → current
Visual Observer · GOI · 3 reports · last 4051d ago
CCD Observer · MAT08 · 3 reports · last 4048d ago
Visual Observer · CAM03 · 3 reports · last 4048d ago
CCD Observer · LEH02 · 3 reports · last 4030d ago
Visual Observer · WYA · 2 reports · last 4048d ago
CCD Observer · PRY01 · 2 reports · last 4024d ago
Visual Observer · GON05 · 1 reports · last 4055d ago
Visual Observer · MAT08 · 1 reports · last 4055d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.