How Is A Comet's Orbit / Course Calculated ?

Answer 1

The basic method is to observe its position over several nights. The subsequent motion of the comet against the background stars is then fitted to a curve that describes the orbit. The difficulty with this method is that a elliptical orbit can resemble a parabolic or hyperbolic orbit at certain sections of the orbit. In the early days of astronomical observations, this closeness made it difficult to determine if a comet was in a closed, periodic orbit or whether it would be on an escape path from the Solar System.

Answer 2

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