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Comet

Iwamoto

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C/2018 Y1 (Iwamoto)

Iwamoto is a comet in the Comet orbit class. Its orbit takes it from 1.29 AU to 287.25 AU from the Sun; one orbit takes 1,732.9 years. Orbit from the JPL solution of 4 January 2024.

Where is it now

Distance from Sun
20.39 AU
True anomaly
151.91°
Distance from Earth
19.599 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 Iwamoto — 20.39 AU from the Sun Iwamoto
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Iwamoto is 19.599 AU from Earth today (2.7 light-hours).

In the sky

Right ascension
23h 23m 09s
Declination
+06° 58′ 16″
Constellation
Pisces
Distance from Earth
19.61 AU
Elongation from the Sun
141.04° — 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
144.27 AU
Eccentricity
0.9911
Inclination
160.4°
Orbital period
1,732.9 years
Perihelion
1.287 AU
Aphelion
287.253 AU
Longitude of ascending node
147.48°
Argument of periapsis
358.06°
Epoch · J2000
2458545.5
Orbit class · COM
Comet
Earth MOID · 116.3 LD
0.2989 AU
Tisserand (Jupiter)
-1.286

Orbit quality

Observations used
2,771
Data arc
348 days
First observed
19 December 2018
Last observed
2 December 2019
Residual RMS
0.51 ″
Solution · Otto Matic
4 January 2024

Visual & observation

Absolute magnitude (H)
13.6
Total magnitude M₁ · K₁ 5.3
13.6

Discovery & classification

Also known as 2018 Y1

Named

Sources