Hartley-IRAS
161P/Hartley-IRAS
Where is it now
- Distance from Sun
- 1.659 AU
- True anomaly
- 298.54°
- As of
- 17 September 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.
In the sky
- Right ascension
- 01h 46m 52s
- Declination
- -24° 20′ 17″
- Constellation
- Fornax
- Distance from Earth
- 0.74 AU
- Elongation from the Sun
- 142.67° — well clear of the Sun
Favours the southern hemisphere; low or below the horizon from far north.
From your location
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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
- 7.719 AU
- Eccentricity
- 0.8362
- Inclination
- 95.74°
- Orbital period
- 21.45 years
- Perihelion
- 1.264 AU
- Aphelion
- 14.175 AU
- Longitude of ascending node
- 1.38°
- Argument of periapsis
- 47.01°
- Epoch · J2000
- 2456369.5
- Orbit class · HTC
- Halley-type comet
- Earth MOID · 169.5 LD
- 0.4356 AU
- Tisserand (Jupiter)
- 0.54
Orbit quality
Orbit very well determined (uncertainty code 0).
- Observations used
- 566
- Data arc
- 42.81 years
- First observed
- 23 November 1983
- Last observed
- 14 September 2026
- Residual RMS
- 0.89 ″
- Solution · Otto Matic
- 15 September 2026
Visual & observation
- Absolute magnitude (H)
- 15.1
- Total magnitude M₁ · K₁ 4.8
- 15.1
Discovery & classification
Also known as 161P
Close approaches 2 on record
| When (UTC) | Body | Distance | Lunar distances | Relative speed |
|---|---|---|---|---|
| 2028-06-02 18:02:00 | Jupiter | 0.3972 AU | 154.6 LD | 19.1 km/s |
Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.
Sources
- orbital elements: JPL SBDB