173P
Not currently visible. Last report 1604 days ago at mag 19.9. Historic peak was mag 16.3. 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
—
J2000
Estimated magnitude
19.9
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
50
Arc unknown
Last observation
1604d ago
Tue, 26 Apr 2022 22:19:11 GMT · COBS consensus
Perihelion
2021-12-19
4.220 au
Peak window
2021-12-16 → 2022-02-05
COBS peak mag 16.3 on 2022-02-02 · perihelion 2021-12-19. Window is those dates ±3 days — not a light-curve fit.
Historic peak
16.3
COBS / analyzed peak 2022-02-02
Catalog ingest
22m ago
Venator last wrote this row 2026-09-17 01:00:03 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
4.220 au
e
0.2620
i
16.50°
Ω
100.00°
ω
29.40°
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).
173P/Mueller
173P · 2026-09-13 22:21:22 UTC → current
Discoverer · parsed-name · 2026-09-13 22:21:22 UTC → current
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Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.