17P
Not currently visible. Last report 1420 days ago at mag 21.9. Historic peak was mag 17.1. 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
—
J2000
Declination
—
J2000
Estimated magnitude
21.9
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
2275
Arc unknown
Last observation
1420d ago
Fri, 28 Oct 2022 06:00:00 GMT · COBS consensus
Perihelion
2028-01-31
2.090 au
Peak window
2028-01-28 → 2028-02-03
COBS peak mag 17.1 on 2028-01-31 · perihelion 2028-01-31. Window is those dates ±3 days — not a light-curve fit.
Historic peak
17.1
COBS / analyzed peak 2028-01-31
Catalog ingest
13m ago
Venator last wrote this row 2026-09-16 22:00:03 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
2.090 au
e
0.4260
i
19.00°
Ω
327.00°
ω
24.60°
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).
17P/Holmes
17P · 2026-09-14 18:27:52 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:52 UTC → current
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1–40 of 201
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.