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Comet

Vaisala-Oterma

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139P/Vaisala-Oterma

Where is it now

Distance from Sun
3.633 AU
True anomaly
313.28°
Distance from Earth
2.791 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 Vaisala-Oterma — 3.633 AU from the Sun Vaisala-Oterma
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Vaisala-Oterma is 2.791 AU from Earth today (23.2 light-minutes).

In the sky

Right ascension
23h 26m 56s
Declination
-00° 41′ 54″
Constellation
Pisces
Distance from Earth
2.8 AU
Elongation from the Sun
142.01° — well clear of the Sun

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
4.526 AU
Eccentricity
0.2474
Inclination
2.33°
Orbital period
9.63 years
Perihelion
3.406 AU
Aphelion
5.646 AU
Longitude of ascending node
242.27°
Argument of periapsis
166.15°
Epoch · J2000
2456416.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 940.1 LD
2.4158 AU
Tisserand (Jupiter)
2.955

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
660
Data arc
87.01 years
First observed
7 October 1939
Last observed
11 October 2026
Residual RMS
0.67 ″
Solution · Otto Matic
14 October 2026

Visual & observation

Absolute magnitude (H)
7.2
Total magnitude M₁ · K₁ 18.5
7.2

Discovery & classification

Also known as 139P · 139P/1939 TN · 139P/1998 WG22

Named

Close approaches 9 on record

When (UTC) Body Distance Lunar distances Relative speed
2042-05-04 14:13:00 Juptr 0.071 AU 27.6 LD 5.1 km/s
2042-05-04 14:13:00 Jupiter 0.071 AU 27.6 LD 5.1 km/s
2046-03-08 22:36:00 Juptr 1.1394 AU 443.4 LD 1.6 km/s
2099-11-19 14:11:00 Juptr 0.8246 AU 320.9 LD 4.3 km/s

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

Sources