423P
423P/Lemmon
Not currently visible. Last report 1271 days ago at mag 20.4. Historic peak was mag 18.6. 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
20.4
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
1
Arc unknown
Last observation
1271d ago
Mon, 27 Mar 2023 03:17:00 GMT · COBS consensus
Perihelion
2021-10-01
5.430 au
Peak window
2021-09-28 → 2022-01-27
COBS peak mag 18.6 on 2022-01-24 · perihelion 2021-10-01. Window is those dates ±3 days — not a light-curve fit.
Historic peak
18.6
COBS / analyzed peak 2022-01-24
Catalog ingest
13m ago
Venator last wrote this row 2026-09-18 03:00:06 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
5.430 au
e
0.1230
i
8.34°
Ω
33.30°
ω
81.40°
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
423P/Lemmon
423P · 2026-09-14 18:28:01 UTC → current
Discoverers
Discoverer · parsed-name · 2026-09-14 18:28:01 UTC → current
Contributors
CCD Observer · MAI01 · 1 reports · last 1271d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.