Key Facts


C/1843 D1 (Great March comet) is a large comet whose orbit does not match any defined comet orbit class. NASA JPL has not classified Great March comet as potentially hazardous because its orbit does not bring it close to Earth.

Great March comet orbits the sun every 187,000 days (511.98 years), coming as close as 0.01 AU and reaching as far as 128.53 AU from the sun. Its orbit is highly elliptical. Based on its brightness and the way it reflects light, Great March comet is probably between 2658.000 to 5943.469 kilometers in diameter, making it the largest asteroid/dwarf planet, very roughly comparable in size to the U.S. state of Alaska.

No Close Approaches

Great March comet's orbit is 0.00 AU from Earth's orbit at its closest point. This means that its orbit is very close to Earth's orbit.

Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.

Images and Observations

Great March comet's orbit is determined by observations dating back to March 5, 1843. It was last officially observed on April 19, 1843. The IAU Minor Planet Center records 200 observations used to determine its orbit.

Accessibility and Exploration

This comet is not considered a viable target for human exploration by the NHATS study.



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Orbital Elements

  • Epoch: 2394259.4 JD
  • Semi-major axis: 64.27 AU
  • Eccentricity: 0.9999
  • Inclination: 144.35°
  • Longitude of Ascending Node: 3.53°
  • Argument of Periapsis: 82.64°
  • Mean Anomaly: 0.0°

Physical Characteristics

  • Diameter: ~3431.463 km

Derived Characteristics

  • Orbit Period: 187,000 days (511.98 years)
  • Avg. Orbit Speed: 3.74 km/s
  • Aphelion Distance: 128.53 AU
  • Perihelion Distance: 0.01 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of C/1843 D1 (Great March comet) is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.