C/1991 X2
Not currently visible. Last report 12575 days ago at mag 38.6. Historic peak was mag 5.2. 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
38.6
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
166
Arc unknown
Last observation
12575d ago
Mon, 13 Apr 1992 09:21:36 GMT · COBS consensus
Perihelion
1992-03-21
0.203 au
Peak window
1992-03-18 → 1992-03-24
COBS peak mag 5.2 on 1992-03-21 · perihelion 1992-03-21. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.2
COBS / analyzed peak 1992-03-21
Catalog ingest
11h ago
Venator last wrote this row 2026-09-16 13:20:16 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
0.203 au
e
1.0000
i
94.40°
Ω
291.00°
ω
307.00°
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).
C/1991 X2 (Mueller)
Informal: Mueller
C/1991 X2 · 2026-09-14 18:27:55 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:55 UTC → current
Visual Observer · HAL · 16 reports · last 12578d ago
Visual Observer · KOR01 · 16 reports · last 12584d ago
Visual Observer · MOD · 14 reports · last 12575d ago
Visual Observer · BOR · 13 reports · last 12582d ago
Visual Observer · KRO02 · 10 reports · last 12616d ago
Visual Observer · GUT · 10 reports · last 12611d ago
Visual Observer · BOU · 9 reports · last 12579d ago
Visual Observer · SPR · 8 reports · last 12620d ago
Visual Observer · COM · 8 reports · last 12639d ago
Visual Observer · REN · 7 reports · last 12583d ago
Visual Observer · MEY · 7 reports · last 12617d ago
Visual Observer · HER02 · 6 reports · last 12619d ago
Visual Observer · MIK · 6 reports · last 12618d ago
Visual Observer · NAK01 · 5 reports · last 12613d ago
Visual Observer · EWA · 5 reports · last 12618d ago
Visual Observer · JAE · 5 reports · last 12614d ago
Visual Observer · LOO01 · 4 reports · last 12617d ago
Visual Observer · KYS · 4 reports · last 12580d ago
Visual Observer · CAM03 · 4 reports · last 12610d ago
Visual Observer · FUC · 3 reports · last 12617d ago
Visual Observer · DAH · 3 reports · last 12622d ago
Visual Observer · VIE · 3 reports · last 12615d ago
Visual Observer · LEH · 3 reports · last 12619d ago
Visual Observer · MOE · 3 reports · last 12624d ago
Visual Observer · PAZ01 · 3 reports · last 12614d ago
Visual Observer · KAS01 · 3 reports · last 12617d ago
Visual Observer · RHE01 · 2 reports · last 12618d ago
Visual Observer · MAR02 · 2 reports · last 12643d ago
Visual Observer · SAR02 · 2 reports · last 12618d ago
Visual Observer · BAU01 · 2 reports · last 12617d ago
Visual Observer · GAR02 · 2 reports · last 12618d ago
Visual Observer · MOR03 · 2 reports · last 12614d ago
Visual Observer · HAS02 · 2 reports · last 12614d ago
Visual Observer · GRA04 · 1 reports · last 12648d ago
Visual Observer · MOR · 1 reports · last 12654d ago
Visual Observer · LEV · 1 reports · last 12626d ago
Visual Observer · NOW · 1 reports · last 12624d ago
Visual Observer · CHE03 · 1 reports · last 12621d ago
Visual Observer · KEE · 1 reports · last 12641d ago
Visual Observer · DEA · 1 reports · last 12626d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.