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Comet

Thomas

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C/1968 Y1 (Thomas)

Thomas is a comet in the Comet orbit class. Its orbit takes it from 3.32 AU to 1,408.46 AU from the Sun; one orbit takes 18,754.8 years. Orbit from the JPL solution of 15 April 2021.

Where is it now

Distance from Sun
79.826 AU
True anomaly
157.14°
Distance from Earth
80.48 AU
As of
25 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 Thomas — 79.826 AU from the Sun Thomas
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Thomas is 80.48 AU from Earth today (11.2 light-hours).

In the sky

Right ascension
15h 30m 26s
Declination
-57° 48′ 36″
Constellation
Norma
Distance from Earth
80.48 AU
Elongation from the Sun
48.48° — 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
705.889 AU
Eccentricity
0.9953
Inclination
45.23°
Orbital period
18,754.8 years
Perihelion
3.316 AU
Aphelion
1,408.461 AU
Longitude of ascending node
16.11°
Argument of periapsis
82.58°
Epoch · J2000
2440266.5
Orbit class · COM
Comet
Earth MOID · 1,050.7 LD
2.6999 AU
Tisserand (Jupiter)
1.596

Orbit quality

Observations used
43
Data arc
150 days
First observed
19 December 1968
Last observed
18 May 1969
Residual RMS
0.66 ″
Solution · Otto Matic
15 April 2021

Visual & observation

Absolute magnitude (H)
5.8
Total magnitude M₁ · K₁ 10.5
5.8

Discovery & classification

Also known as 1968 Y1

Named

Sources