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Comet

Leonard

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C/2021 U4 (Leonard)

Leonard is a comet in the Comet orbit class. Its orbit takes it from 1.79 AU to 86.14 AU from the Sun; one orbit takes 291.5 years. Orbit from the JPL solution of 14 January 2025.

Where is it now

Distance from Sun
13.883 AU
True anomaly
141.21°
Distance from Earth
14.841 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 Leonard — 13.883 AU from the Sun Leonard
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Leonard is 14.841 AU from Earth today (2.1 light-hours).

In the sky

Right ascension
14h 56m 44s
Declination
-08° 41′ 44″
Constellation
Libra
Distance from Earth
14.85 AU
Elongation from the Sun
14.65° — too close to the Sun to observe

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
43.964 AU
Eccentricity
0.9593
Inclination
152.88°
Orbital period
291.5 years
Perihelion
1.787 AU
Aphelion
86.14 AU
Longitude of ascending node
241.8°
Argument of periapsis
237.29°
Epoch · J2000
2459514.5
Orbit class · COM
Comet
Earth MOID · 358.4 LD
0.9208 AU
Tisserand (Jupiter)
-1.342

Orbit quality

Orbit poorly determined (uncertainty code 6).

Observations used
37
Data arc
53 days
First observed
16 September 2021
Last observed
8 November 2021
Residual RMS
0.32 ″
Solution · Otto Matic
14 January 2025

Visual & observation

Absolute magnitude (H)
18.8
Total magnitude M₁ · K₁ 4.5
18.8

Discovery & classification

Also known as 2021 U4

Named

Sources