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Trans-Neptunian object

1999 OG4

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(1999 OG4)

1999 OG4 is a trans-Neptunian object in the Trans-Neptunian object orbit class. Its orbit takes it from 40.66 AU to 53.13 AU from the Sun; one orbit takes 321.2 years. Orbit from the JPL solution of 14 April 2021.

Where is it now

Distance from Sun
50.329 AU
True anomaly
129.56°
Distance from Earth
49.688 AU
As of
24 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 — 0.994 AU from the Sun Earth 1999 OG4 — 50.329 AU from the Sun 1999 OG4
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 1999 OG4 is 49.688 AU from Earth today (6.9 light-hours).

In the sky

Right ascension
22h 51m 41s
Declination
-08° 27′ 31″
Constellation
Aquarius
Distance from Earth
49.7 AU
Elongation from the Sun
128.9° — well clear of the Sun

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
46.897 AU
Eccentricity
0.1329
Inclination
1.42°
Orbital period
321.2 years
Perihelion
40.664 AU
Aphelion
53.13 AU
Longitude of ascending node
111.34°
Argument of periapsis
101.01°
Epoch · J2000
2461200.5
Orbit class · TNO
Trans-Neptunian object
Earth MOID · 15,434.2 LD
39.6591 AU
Tisserand (Jupiter)
6.06

Orbit quality

Orbit poorly determined (uncertainty code 6).

Observations used
18
Data arc
738 days
First observed
20 July 1999
Last observed
27 July 2001
Residual RMS
0.3 ″
Solution · Otto Matic
14 April 2021

Visual & observation

Absolute magnitude (H)
7.7

Discovery & classification

TNO

Sources