421P
421P/McNaught
Not visible to typical instruments. Current estimate mag 28.1. Historic peak was mag 18.2. Visual and most CCD amateur setups will not see it. Space telescopes or large ground telescopes are the remaining path.
Right ascension
—
J2000
Declination
—
J2000
Estimated magnitude
28.1
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
0
Arc unknown
Last observation
Not in feed
COBS consensus does not publish an observer timestamp. Catalog ingested 2d ago.
Perihelion
2021-01-22
1.650 au
Peak window
2021-01-19 → 2021-01-25
COBS peak mag 18.2 on 2021-01-22 · perihelion 2021-01-22. Window is those dates ±3 days — not a light-curve fit.
Historic peak
18.2
COBS / analyzed peak 2021-01-22
Catalog ingest
2d ago
Venator last wrote this row 2026-09-14 20:00:15 UTC
Light curve
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.
Orbital elements
q
1.650 au
e
0.6740
i
10.10°
Ω
55.30°
ω
260.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
—
Reporting sources
COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
Name history
421P/McNaught
421P · 2026-09-14 18:27:52 UTC → current
Discoverers
Discoverer · parsed-name · 2026-09-14 18:27:52 UTC → current
Contributors
- No recent COBS visual or CCD reports linked yet.
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.