This dataset is due to Johannes Kepler and is reported in his famous work, Astronomia nova, published in 1609.

It corresponds to observations of Mars carried out at various oppositions during the Earth years 1582-1595. Actually, these data points are not quite "raw" and were intended, by Kepler, merely to illustrate (not prove) his theory of Mars.

The graph shows the radius of Mars as a function of eccentric anomaly.


y = A/(1 + B cos (x)) [an ellipse, in polar coordinates]