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Trans-Neptunian object

2013 RT128

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(2013 RT128)

Where is it now

Distance from Sun
43.275 AU
True anomaly
137.31°
Distance from Earth
42.281 AU
As of
17 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.

Sun Earth — 0.996 AU from the Sun Earth 2013 RT128 — 43.275 AU from the Sun 2013 RT128
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2013 RT128 is 42.281 AU from Earth today (5.9 light-hours).

In the sky

Right ascension
01h 35m 02s
Declination
+05° 40′ 48″
Constellation
Pisces
Distance from Earth
42.28 AU
Elongation from the Sun
176° — 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
40.384 AU
Eccentricity
0.1048
Inclination
24.15°
Orbital period
256.6 years
Perihelion
36.151 AU
Aphelion
44.618 AU
Longitude of ascending node
32.73°
Argument of periapsis
213.26°
Epoch · J2000
2461200.5
Orbit class · TNO
Trans-Neptunian object
Earth MOID · 13,684.9 LD
35.1641 AU
Tisserand (Jupiter)
5.185

Orbit quality

Orbit reasonably well determined (uncertainty code 3).

Observations used
39
Data arc
12.12 years
First observed
10 September 2013
Last observed
25 October 2025
Residual RMS
0.21 ″
Solution · Otto Matic
11 March 2026

Visual & observation

Absolute magnitude (H)
7.29

Discovery & classification

TNO

Sources