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Comet

Helin-Roman-Alu

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C/1989 T1 (Helin-Roman-Alu)

Helin-Roman-Alu is a comet in the Comet orbit class. Its orbit takes it from 1.05 AU to 222.12 AU from the Sun; one orbit takes 1,178.7 years. Orbit from the JPL solution of 15 April 2021.

Where is it now

Distance from Sun
57.662 AU
True anomaly
166.65°
Distance from Earth
58.413 AU
As of
24 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 — 0.994 AU from the Sun Earth Helin-Roman-Alu — 57.662 AU from the Sun Helin-Roman-Alu
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Helin-Roman-Alu is 58.413 AU from Earth today (8.1 light-hours).

In the sky

Right ascension
14h 25m 02s
Declination
-52° 10′ 19″
Constellation
Lupus
Distance from Earth
58.42 AU
Elongation from the Sun
40.3° — 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
111.583 AU
Eccentricity
0.9906
Inclination
46.04°
Orbital period
1,178.7 years
Perihelion
1.047 AU
Aphelion
222.119 AU
Longitude of ascending node
8.52°
Argument of periapsis
68.13°
Epoch · J2000
2447847.5
Orbit class · COM
Comet
Earth MOID · 145.9 LD
0.3749 AU
Tisserand (Jupiter)
0.925

Orbit quality

Observations used
120
Data arc
118 days
First observed
29 September 1989
Last observed
25 January 1990
Residual RMS
0.83 ″
Solution · Otto Matic
15 April 2021

Visual & observation

Absolute magnitude (H)
12.5
Total magnitude M₁ · K₁ 13.8
12.5

Discovery & classification

Also known as 1989 T1

Named

Sources