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Comet

McNaught

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421P/McNaught

Where is it now

Distance from Sun
8.511 AU
True anomaly
179.5°
Distance from Earth
8.827 AU
As of
22 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.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.995 AU from the Sun Earth McNaught — 8.511 AU from the Sun McNaught
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. McNaught is 8.827 AU from Earth today (1.2 light-hours).

In the sky

Right ascension
09h 48m 02s
Declination
+23° 26′ 51″
Constellation
Leo
Distance from Earth
8.81 AU
Elongation from the Sun
69.14° — 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
5.08 AU
Eccentricity
0.6754
Inclination
10.09°
Orbital period
11.45 years
Perihelion
1.649 AU
Aphelion
8.512 AU
Longitude of ascending node
55.68°
Argument of periapsis
259.9°
Epoch · J2000
2455509.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 261.6 LD
0.6722 AU
Tisserand (Jupiter)
2.459

Orbit quality

Orbit very well determined (uncertainty code 1).

Observations used
96
Data arc
12.05 years
First observed
11 October 2009
Last observed
31 October 2021
Residual RMS
0.68 ″
Solution · Otto Matic
24 April 2023

Visual & observation

Absolute magnitude (H)
13.7
Total magnitude M₁ · K₁ 13.3
13.7

Discovery & classification

Also known as 421P · 421P/2009 U4 · 421P/2020 H10

Named

Close approaches 1 on record

When (UTC) Body Distance Lunar distances Relative speed
2183-05-11 09:27:00 Satrn 1.5793 AU 614.6 LD 4.8 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources