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Trans-Neptunian object

15789

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15789 (1993 SC)

Where is it now

Distance from Sun
39.731 AU
True anomaly
100.94°
Distance from Earth
38.868 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 15789 — 39.731 AU from the Sun 15789
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 15789 is 38.868 AU from Earth today (5.4 light-hours).

In the sky

Right ascension
03h 23m 41s
Declination
+23° 16′ 37″
Constellation
Aries
Distance from Earth
38.87 AU
Elongation from the Sun
149.7° — 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.

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
39.683 AU
Eccentricity
0.1835
Inclination
5.16°
Orbital period
250 years
Perihelion
32.4 AU
Aphelion
46.966 AU
Longitude of ascending node
354.73°
Argument of periapsis
318.2°
Epoch · J2000
2461200.5
Orbit class · TNO
Trans-Neptunian object
Earth MOID · 12,215.1 LD
31.3874 AU
Tisserand (Jupiter)
5.539

Orbit quality

Orbit very well determined (uncertainty code 2).

Observations used
146
Data arc
26.32 years
First observed
23 September 1993
Last observed
19 January 2020
Residual RMS
0.69 ″
Solution · Otto Matic
13 April 2021

Physical properties

Mean radius
164 km

Visual & observation

Geometric albedo
0.022
Absolute magnitude (H)
7.09

Discovery & classification

Discovered by
Williams, I. P., Fitzsimmons, A., O'Ceallaigh, D.
Discovery date
17 September 1993
Discovery site
La Palma

Also known as 1993 SC

TNO

Sources