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Asteroid

Antigone

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129 Antigone (A873 CA)

Where is it now

Distance from Sun
3.356 AU
True anomaly
149.85°
Distance from Earth
2.401 AU
As of
22 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.995 AU from the Sun Earth Antigone — 3.356 AU from the Sun Antigone
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Antigone is 2.401 AU from Earth today (20.0 light-minutes).

In the sky

Right ascension
02h 45m 55s
Declination
-01° 51′ 13″
Constellation
Eridanus
Distance from Earth
2.4 AU
Elongation from the Sun
160.93° — near opposition — up most of the night

Visible from both hemispheres.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
2.868 AU
Eccentricity
0.2132
Inclination
12.27°
Orbital period
4.86 years
Perihelion
2.256 AU
Aphelion
3.479 AU
Longitude of ascending node
135.66°
Argument of periapsis
110.48°
Epoch · J2000
2461200.5
Orbit class · MBA
Main-belt asteroid
Earth MOID · 497.2 LD
1.2775 AU
Tisserand (Jupiter)
3.232

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
5,542
Data arc
149.1 years
First observed
7 December 1876
Last observed
1 January 2026
Residual RMS
0.39 ″
Solution · Otto Matic
11 March 2026

Physical properties

Mean radius
57 km
Rotation period
4.96 hours

Visual & observation

Geometric albedo
0.151
Absolute magnitude (H)
7.02
Colour index (B–V)
0.72
Spectral type (SMASS)
X
Spectral type (Tholen)
M
Colour index (U–B)
0.25

Discovery & classification

Discovered by
Peters, C. H. F.
Discovery date
5 February 1873
Discovery site
Clinton

Also known as 129 · A873 CA · A878 CA · A907 BA

Main-Belt Asteroid Named

Close approaches 9 on record

When (UTC) Body Distance Lunar distances Relative speed
2037-10-16 18:29:00 Juptr 1.9909 AU 774.8 LD 3.2 km/s
2070-02-23 21:00:00 Juptr 1.9977 AU 777.4 LD 3.5 km/s
2095-02-14 21:57:00 Juptr 1.764 AU 686.5 LD 0.9 km/s
2120-02-07 17:54:00 Juptr 1.7886 AU 696.1 LD 2 km/s
2177-05-17 03:02:00 Juptr 1.9078 AU 742.4 LD 2.5 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources