C/2025 D1
C/2025 D1 (Groeller)
Not currently visible. Last report 542 days ago at mag 18.7. 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
—
J2000
Declination
—
J2000
Estimated magnitude
18.7
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
3
Arc unknown
Last observation
542d ago
Sun, 23 Mar 2025 21:40:00 GMT · COBS consensus
Perihelion
2028-05-23
14.100 au
Peak window
2028-02-02 → 2028-05-26
COBS peak mag 18.3 on 2028-02-05 · perihelion 2028-05-23. Window is those dates ±3 days — not a light-curve fit.
Historic peak
18.3
COBS / analyzed peak 2028-02-05
Catalog ingest
24m ago
Venator last wrote this row 2026-09-17 04:00:05 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
14.100 au
e
1.0000
i
84.40°
Ω
313.00°
ω
186.00°
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
C/2025 D1 (Groeller)
Informal: Groeller
C/2025 D1 · 2026-09-13 22:21:23 UTC → current
Discoverers
Discoverer · parsed-name · 2026-09-13 22:21:23 UTC → current
Contributors
CCD Observer · MAI01 · 1 reports · last 572d ago
CCD Observer · RYS · 1 reports · last 570d ago
CCD Observer · CAR06 · 1 reports · last 542d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.