27P
Not currently visible. Last report 5548 days ago at mag 43.1. Historic peak was mag 7.4. 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
43.1
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
266
Arc unknown
Last observation
5548d ago
Sat, 09 Jul 2011 18:00:00 GMT · COBS consensus
Perihelion
2039-05-13
0.738 au
Peak window
2011-07-29 → 2039-05-16
COBS peak mag 7.4 on 2011-08-01 · perihelion 2039-05-13. Window is those dates ±3 days — not a light-curve fit.
Historic peak
7.4
COBS / analyzed peak 2011-08-01
Catalog ingest
2d ago
Venator last wrote this row 2026-09-14 20:00:16 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
0.738 au
e
0.9200
i
29.40°
Ω
251.00°
ω
196.00°
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).
27P/Crommelin
27P · 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 42
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.