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Comet Near-Earth

Lemmon

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C/2023 S3 (Lemmon)

Lemmon is a comet in the Halley-type comet orbit class. Its orbit takes it from 0.83 AU to 56.11 AU from the Sun; one orbit takes 151.9 years. Orbit from the JPL solution of 2 August 2024.

Where is it now

Distance from Sun
9.852 AU
True anomaly
149.2°
Distance from Earth
10.463 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 — 9.852 AU from the Sun Lemmon
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Lemmon is 10.463 AU from Earth today (1.5 light-hours).

In the sky

Right ascension
12h 35m 53s
Declination
+34° 06′ 24″
Constellation
Canes Venatici
Distance from Earth
10.46 AU
Elongation from the Sun
50.23° — near the Sun — look low at dusk or dawn

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
28.469 AU
Eccentricity
0.9708
Inclination
140.5°
Orbital period
151.9 years
Perihelion
0.83 AU
Aphelion
56.108 AU
Longitude of ascending node
233.83°
Argument of periapsis
281.57°
Epoch · J2000
2460300.5
Orbit class · HTC
Halley-type comet
Earth MOID · 85.0 LD
0.2183 AU
Tisserand (Jupiter)
-0.683

Orbit quality

Orbit very well determined (uncertainty code 2).

Observations used
692
Data arc
251 days
First observed
25 September 2023
Last observed
2 June 2024
Residual RMS
0.46 ″
Solution · Otto Matic
2 August 2024

Visual & observation

Absolute magnitude (H)
16.3
Total magnitude M₁ · K₁ 9
16.3

Discovery & classification

Also known as 2023 S3

Near-Earth Object Named

Sources