Trans-Neptunian object

Otrera

385571 Otrera (2004 UP10)

Where is it now

Distance from Sun: 29.372 AU
True anomaly: 11.57°
Distance from Earth: 28.533 AU
As of: 15 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.

Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Otrera is 28.533 AU from Earth today (4.0 light-hours).

In the sky

Right ascension: 03h 32m 29s
Declination: +19° 38′ 22″
Constellation: Taurus
Distance from Earth: 28.53 AU
Elongation from the Sun: 147.05° — well clear of the Sun

Favours the northern hemisphere; low or below the horizon from far south.

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.

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How do I find my coordinates?

Google Maps on a computer

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

Google Maps on a phone

Press and hold the spot to drop a pin.
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.

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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: 30.285 AU
Eccentricity: 0.0307
Inclination: 1.43°
Orbital period: 166.7 years
Perihelion: 29.354 AU
Aphelion: 31.216 AU
Longitude of ascending node: 34.81°
Argument of periapsis: 8.14°
Epoch · J2000: 2461200.5
Orbit class · TNO: Trans-Neptunian object
Earth MOID · 11,037.6 LD: 28.3618 AU
Tisserand (Jupiter): 4.993

Orbit quality

Orbit reasonably well determined (uncertainty code 4).

Observations used: 31
Data arc: 10.93 years
First observed: 31 October 2002
Last observed: 6 October 2013
Residual RMS: 0.27 ″
Solution · Otto Matic: 14 April 2021

Visual & observation

Absolute magnitude (H): 8.91

Discovery & classification

Discovered by: Sheppard, S. S., Trujillo, C.
Discovery date: 16 October 2004
Discovery site: Las Campanas

Otrera was the first queen of the Amazons. She was involved with Ares and was the mother of the Amazons queen Penthesilea, who led the Amazons in the Trojan war.

Also known as 385571 · 2004 UP10

Named TNO

Sources

visual properties: JPL SBDB (lookup)
orbital elements: JPL SBDB