109P
Not currently visible. Last report 12221 days ago at mag 37.2. Historic peak was mag 5.3. 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
37.2
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
1626
Arc unknown
Last observation
12221d ago
Thu, 01 Apr 1993 18:57:36 GMT · COBS consensus
Perihelion
1992-12-21
0.966 au
Peak window
1992-12-10 → 1992-12-24
COBS peak mag 5.3 on 1992-12-13 · perihelion 1992-12-21. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.3
COBS / analyzed peak 1992-12-13
Catalog ingest
9h 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
0.966 au
e
0.9630
i
113.00°
Ω
140.00°
ω
153.00°
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).
109P/Swift-Tuttle
109P · 2026-09-14 18:27:54 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:54 UTC → current
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1–40 of 261
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.