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Comet

Erasmus

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C/2020 S3 (Erasmus)

Erasmus is a comet in the Comet orbit class. Its orbit takes it from 0.4 AU to 389.27 AU from the Sun; one orbit takes 2,719.6 years. Orbit from the JPL solution of 29 April 2024.

Where is it now

Distance from Sun
17.715 AU
True anomaly
163.14°
Distance from Earth
16.764 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 Erasmus — 17.715 AU from the Sun Erasmus
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Erasmus is 16.764 AU from Earth today (2.3 light-hours).

In the sky

Right ascension
00h 46m 07s
Declination
+15° 08′ 01″
Constellation
Pisces
Distance from Earth
16.77 AU
Elongation from the Sun
161.81° — near opposition — up most of the night

Favours the northern hemisphere; low or below the horizon from far south.

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
194.833 AU
Eccentricity
0.998
Inclination
19.86°
Orbital period
2,719.6 years
Perihelion
0.398 AU
Aphelion
389.268 AU
Longitude of ascending node
222.99°
Argument of periapsis
349.89°
Epoch · J2000
2459284.5
Orbit class · COM
Comet
Earth MOID · 122.7 LD
0.3153 AU
Tisserand (Jupiter)
0.762

Orbit quality

Observations used
861
Data arc
436 days
First observed
17 September 2020
Last observed
27 November 2021
Residual RMS
0.61 ″
Solution · Otto Matic
29 April 2024

Visual & observation

Absolute magnitude (H)
13
Total magnitude M₁ · K₁ 4.5
13

Discovery & classification

Also known as 2020 S3

Named

Sources