C/2005 EL173
Not currently visible. Last report 7157 days ago at mag 27.2. Historic peak was mag 17.3. 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
—
J2000
Declination
—
J2000
Estimated magnitude
27.2
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
3
Arc unknown
Last observation
7157d ago
Mon, 12 Feb 2007 11:45:36 GMT · COBS consensus
Perihelion
2007-02-28
3.870 au
Peak window
2007-02-18 → 2007-03-03
COBS peak mag 17.3 on 2007-02-21 · perihelion 2007-02-28. Window is those dates ±3 days — not a light-curve fit.
Historic peak
17.3
COBS / analyzed peak 2007-02-21
Catalog ingest
13h 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.
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.
q
3.870 au
e
1.0000
i
131.00°
Ω
345.00°
ω
261.00°
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/2005 EL173 (LONEOS)
Informal: LONEOS
C/2005 EL173 · 2026-09-14 18:27:53 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:53 UTC → current
CCD Observer · NAK01 · 1 reports · last 7840d ago
CCD Observer · TSU02 · 1 reports · last 7157d ago
CCD Observer · OHS · 1 reports · last 7501d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.