C/1917 F1
C/1917 F1 (Mellish) 23a (11)
Not currently visible. Last report 39997 days ago at mag 33.8. 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
02h 45m 27s
J2000
Declination
−12° 42′ 11″
J2000
Estimated magnitude
33.8
Professional survey · COBS consensus
Confidence
48
Class D · priority 54
Observations
3
Arc unknown
Last observation
39997d ago
Sat, 05 May 1917 21:21:00 GMT · COBS consensus
Perihelion
2061-07-24
0.206 au
Peak window
2061-07-21 → 2061-07-27
COBS peak mag 5.2 on 2061-07-24 · perihelion 2061-07-24. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.2
COBS / analyzed peak 2061-07-24
Catalog ingest
15h ago
Venator last wrote this row 2026-11-06 14:20:24 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.
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
0.206 au
e
0.9925
i
32.78°
Ω
87.70°
ω
122.19°
a
27.506 au
MOID
—
H
0.0
H0 / n
0.0 / 0
NEO score
—
PHA score
—
RMS
—
Elongation
151°
Reporting sources
COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
MPC AllCometEls
okFull MPC comet orbit catalog. Stored even when fainter than the UI default of mag 22.
Name history
C/1917 F1 (Mellish) 23a (11)
Informal: Mellish) 23a (11
C/1917 F1 · 2026-11-06 14:20:24 UTC → current
C/1917 F1 (Mellish)
Informal: Mellish
C/1917 F1 · 2026-11-05 14:20:26 UTC → 2026-11-06 14:20:24 UTC
C/1917 F1 (Mellish) 23a (11)
Informal: Mellish) 23a (11
C/1917 F1 · 2026-10-30 13:20:26 UTC → 2026-11-05 14:20:26 UTC
C/1917 F1 (Mellish)
Informal: Mellish
C/1917 F1 · 2026-10-25 13:20:22 UTC → 2026-10-30 13:20:26 UTC
C/1917 F1 (Mellish) 23a (11)
Informal: Mellish) 23a (11
C/1917 F1 · 2026-10-14 13:20:34 UTC → 2026-10-25 13:20:22 UTC
C/1917 F1 (Mellish)
Informal: Mellish
C/1917 F1 · 2026-10-13 13:20:29 UTC → 2026-10-14 13:20:34 UTC
C/1917 F1 (Mellish) 23a (11)
Informal: Mellish) 23a (11
C/1917 F1 · 2026-09-14 18:28:02 UTC → 2026-10-13 13:20:29 UTC
Discoverers
Discoverer · parsed-name · 2026-09-14 18:28:02 UTC → current
Contributors
CCD Observer · LOV · 3 reports · last 39997d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.