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Comet

Seki

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C/1961 T1 (Seki)

Seki is a comet in the Comet orbit class. Its orbit takes it from 0.68 AU to 172.87 AU from the Sun; one orbit takes 808.4 years. Orbit from the JPL solution of 15 April 2021.

Where is it now

Distance from Sun
80.239 AU
True anomaly
172.25°
Distance from Earth
80.166 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 Seki — 80.239 AU from the Sun Seki
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Seki is 80.166 AU from Earth today (11.1 light-hours).

In the sky

Right ascension
20h 57m 22s
Declination
-39° 16′ 25″
Constellation
Microscopium
Distance from Earth
80.18 AU
Elongation from the Sun
93.19° — well clear of the Sun

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
86.778 AU
Eccentricity
0.9922
Inclination
155.71°
Orbital period
808.4 years
Perihelion
0.681 AU
Aphelion
172.874 AU
Longitude of ascending node
247.36°
Argument of periapsis
126.59°
Epoch · J2000
2437615.5
Orbit class · COM
Comet
Earth MOID · 32.7 LD
0.0841 AU
Tisserand (Jupiter)
-0.871

Orbit quality

Orbit poorly determined (uncertainty code 6).

Observations used
15
Data arc
75 days
First observed
15 October 1961
Last observed
29 December 1961
Residual RMS
0.37 ″
Solution · Otto Matic
15 April 2021

Discovery & classification

Also known as 1961 T1

Named

Sources