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Comet Near-Earth

Perrine-Mrkos

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18D/Perrine-Mrkos

Where is it now

Distance from Sun
5.572 AU
True anomaly
193.44°
Distance from Earth
6.35 AU
As of
11 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 — 0.998 AU from the Sun Earth Perrine-Mrkos — 5.572 AU from the Sun Perrine-Mrkos
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Perrine-Mrkos is 6.35 AU from Earth today (52.8 light-minutes).

In the sky

Right ascension
15h 28m 17s
Declination
-19° 00′ 39″
Constellation
Libra
Distance from Earth
6.35 AU
Elongation from the Sun
35.38° — 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
3.56 AU
Eccentricity
0.6426
Inclination
17.76°
Orbital period
6.72 years
Perihelion
1.272 AU
Aphelion
5.847 AU
Longitude of ascending node
240.88°
Argument of periapsis
166.05°
Epoch · J2000
2440240.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 112.6 LD
0.2892 AU
Tisserand (Jupiter)
2.669

Orbit quality

Orbit very well determined (uncertainty code 1).

Observations used
16
Data arc
7.07 years
First observed
29 November 1961
Last observed
26 December 1968
Residual RMS
1.65 ″
Solution · M.S.W. Keesey
22 February 2002

Visual & observation

Absolute magnitude (H)
11.5
Total magnitude M₁ · K₁ 20
11.5

Discovery & classification

Also known as 18D · 1896 VII · 1896g · 18D/1896 X1 · 18D/1909 P1 · 18D/1955 U1 · 1909 III · 1909b

Near-Earth Object Named

Close approaches 15 on record

When (UTC) Body Distance Lunar distances Relative speed
2030-09-07 12:17:00 Juptr 0.2716 AU 105.7 LD 7.7 km/s
2030-09-07 12:17:00 Jupiter 0.2716 AU 105.7 LD 7.7 km/s
2039-08-16 21:51:00 Mars 0.2513 AU 97.8 LD 12.9 km/s
2041-06-06 14:35:00 Juptr 1.9255 AU 749.4 LD 10.7 km/s
2065-12-30 19:46:00 Juptr 1.8854 AU 733.7 LD 11.6 km/s
2076-12-28 05:37:00 Juptr 0.9308 AU 362.2 LD 6.8 km/s

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

Sources