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Comet Near-Earth

Hartley-IRAS

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161P/Hartley-IRAS

Where is it now

Distance from Sun
1.442 AU
True anomaly
318.46°
Distance from Earth
0.587 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.

Sun Earth — 0.998 AU from the Sun Earth Hartley-IRAS — 1.442 AU from the Sun Hartley-IRAS
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Hartley-IRAS is 0.587 AU from Earth today (4.9 light-minutes).

In the sky

Right ascension
21h 40m 54s
Declination
+01° 02′ 29″
Constellation
Aquarius
Distance from Earth
0.59 AU
Elongation from the Sun
127.48° — 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
7.726 AU
Eccentricity
0.8347
Inclination
95.64°
Orbital period
21.47 years
Perihelion
1.277 AU
Aphelion
14.174 AU
Longitude of ascending node
1.31°
Argument of periapsis
46.91°
Epoch · J2000
2458368.5
Orbit class · HTC
Halley-type comet
Earth MOID · 174.7 LD
0.449 AU
Tisserand (Jupiter)
0.542

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
1,011
Data arc
42.85 years
First observed
3 December 1983
Last observed
9 October 2026
Residual RMS
0.79 ″
Solution · Otto Matic
9 October 2026

Visual & observation

Absolute magnitude (H)
15.2
Total magnitude M₁ · K₁ 4.5
15.2

Discovery & classification

Also known as 161P · 161P/1983 V1 · 161P/2004 V2 · 1983v · 1984 III

Near-Earth Object Named

Close approaches 5 on record

When (UTC) Body Distance Lunar distances Relative speed
2028-06-02 18:05:00 Jupiter 0.3971 AU 154.5 LD 19.1 km/s
2028-06-02 18:06:00 Juptr 0.3971 AU 154.6 LD 19.1 km/s
2171-01-31 10:34:00 Juptr 0.6382 AU 248.4 LD 21.1 km/s

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

Sources