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Early warning for newly discovered comets and unconfirmed objects.

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C/1965 S1-A

C/1965 S1 (Ikeya-Seki) A

CometClass Ecatalogued
Unknown

Not currently visible. Last report 22188 days ago at mag 37.4. Historic peak was mag -12.7. Typical backyard telescopes will not show it. HST, JWST, or an 8–10 m class telescope might recover it with a good ephemeris.

Active comet in COBS

JSONCSV

Right ascension

—

J2000

Declination

—

J2000

Estimated magnitude

37.4

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

200

Arc unknown

Last observation

22188d ago

Fri, 17 Dec 1965 14:24:00 GMT · COBS consensus

Perihelion

1965-11-23

0.010 au

Peak window

1965-11-20 → 1965-11-26

COBS peak mag -12.7 on 1965-11-23 · perihelion 1965-11-23. Window is those dates ±3 days — not a light-curve fit.

Historic peak

-12.7

COBS / analyzed peak 1965-11-23

Catalog ingest

12h ago

Venator last wrote this row 2026-09-16 13:20:17 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

0.010 au

e

1.0000

i

147.00°

Ω

85.80°

ω

7.53°

a

—

MOID

—

H

—

H0 / n

—

NEO score

—

PHA score

—

RMS

—

Elongation

—

Reporting sources

  • COBS comet list

    ok

    Comet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).

Name history

  • C/1965 S1 (Ikeya-Seki) A

    C/1965 S1-A · 2026-09-14 18:27:57 UTC → current

Discoverers

  • Ikeya-Seki

    Discoverer · parsed-name · 2026-09-14 18:27:57 UTC → current

Contributors

Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.