C/2023 X1
Not currently visible. Last report 383 days ago at mag 26.7. Historic peak was mag 14.4. 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
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J2000
Declination
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J2000
Estimated magnitude
26.7
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
10
Arc unknown
Last observation
383d ago
Sat, 30 Aug 2025 01:57:00 GMT · COBS consensus
Perihelion
2023-10-17
0.954 au
Peak window
2023-10-14 → 2023-10-30
COBS peak mag 14.4 on 2023-10-27 · perihelion 2023-10-17. Window is those dates ±3 days — not a light-curve fit.
Historic peak
14.4
COBS / analyzed peak 2023-10-27
Catalog ingest
12h ago
Venator last wrote this row 2026-09-16 13:20:20 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
0.954 au
e
0.9940
i
111.00°
Ω
137.00°
ω
322.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2023 X1 (Leonard)
Informal: Leonard
C/2023 X1 · 2026-09-14 18:28:02 UTC → current
Discoverer · parsed-name · 2026-09-14 18:28:02 UTC → current
CCD Observer · CAR06 · 4 reports · last 383d ago
CCD Observer · PAP04 · 1 reports · last 1000d ago
CCD Observer · YOS02 · 1 reports · last 1000d ago
CCD Observer · HIL04 · 1 reports · last 996d ago
CCD Observer · MAS01 · 1 reports · last 1014d ago
CCD Observer · DEK01 · 1 reports · last 982d ago
CCD Observer · FRI02 · 1 reports · last 1004d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.