391P
Not currently visible. Last report 581 days ago at mag 18.1. Historic peak was mag 16.7. 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
16h 20m 03s
J2000
Declination
−06° 21′ 49″
J2000
Estimated magnitude
18.1
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
6
Arc unknown
Last observation
581d ago
Sat, 05 Apr 2025 01:11:59 GMT · COBS consensus
Perihelion
2028-05-08
4.140 au
Peak window
2028-05-05 → 2028-08-16
COBS peak mag 16.7 on 2028-08-13 · perihelion 2028-05-08. Window is those dates ±3 days — not a light-curve fit.
Historic peak
16.7
COBS / analyzed peak 2028-08-13
Catalog ingest
23m ago
Venator last wrote this row 2026-11-07 03:30:21 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
4.140 au
e
0.1180
i
21.30°
Ω
125.00°
ω
187.00°
a
4.700 au
MOID
—
H
—
H0 / n
8.0 / 4
NEO score
—
PHA score
—
RMS
—
Elongation
25°
COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
COBS orbits
okOsculating elements and photometric parameters (H0, n) for active comets.
391P/Kowalski
391P · 2026-09-13 22:21:23 UTC → current
Discoverer · parsed-name · 2026-09-13 22:21:23 UTC → current
CCD Observer · HIL04 · 4 reports · last 2566d ago
CCD Observer · SRB · 1 reports · last 6962d ago
CCD Observer · FRI02 · 1 reports · last 581d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.