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Comet

Lemmon

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C/2023 H2 (Lemmon)

Lemmon is a comet in the Comet orbit class. Its orbit takes it from 0.89 AU to 480.21 AU from the Sun; one orbit takes 3,730.9 years. Orbit from the JPL solution of 30 July 2024.

Where is it now

Distance from Sun
10.778 AU
True anomaly
146.87°
Distance from Earth
11.236 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 Lemmon — 10.778 AU from the Sun Lemmon
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Lemmon is 11.236 AU from Earth today (1.6 light-hours).

In the sky

Right ascension
15h 03m 42s
Declination
-71° 22′ 21″
Constellation
Apus
Distance from Earth
11.25 AU
Elongation from the Sun
59.91° — near the Sun — look low at dusk or dawn

Favours the southern hemisphere; low or below the horizon from far north.

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
240.55 AU
Eccentricity
0.9963
Inclination
113.75°
Orbital period
3,730.9 years
Perihelion
0.894 AU
Aphelion
480.207 AU
Longitude of ascending node
217.04°
Argument of periapsis
150.65°
Epoch · J2000
2460224.5
Orbit class · COM
Comet
Earth MOID · 14.1 LD
0.0361 AU
Tisserand (Jupiter)
-0.45

Orbit quality

Observations used
724
Data arc
292 days
First observed
26 March 2023
Last observed
12 January 2024
Residual RMS
0.64 ″
Solution · Otto Matic
30 July 2024

Visual & observation

Absolute magnitude (H)
16.1
Total magnitude M₁ · K₁ 5.5
16.1

Discovery & classification

Also known as 2023 H2

Named

Sources