C/2005 T4
Not currently visible. Last report 7624 days ago at mag 33.0. Historic peak was mag 12.2. 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
33.0
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
6
Arc unknown
Last observation
7624d ago
Tue, 01 Nov 2005 16:47:59 GMT · COBS consensus
Perihelion
2034-05-29
0.658 au
Peak window
2034-05-26 → 2034-07-02
COBS peak mag 12.2 on 2034-06-29 · perihelion 2034-05-29. Window is those dates ±3 days — not a light-curve fit.
Historic peak
12.2
COBS / analyzed peak 2034-06-29
Catalog ingest
12h ago
Venator last wrote this row 2026-09-16 13:20:18 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.
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
0.658 au
e
0.9300
i
160.00°
Ω
25.90°
ω
41.90°
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/2005 T4 (SWAN)
Informal: SWAN
C/2005 T4 · 2026-09-14 18:27:58 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:58 UTC → current
Visual Observer · PAR03 · 3 reports · last 7624d ago
Visual Observer · GON05 · 1 reports · last 7630d ago
CCD Observer · TSU02 · 1 reports · last 7634d ago
Visual Observer · YOS04 · 1 reports · last 7633d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.