I have a reasonable understanding of Kepler's Equation up to a point. It is written as: M = E - e sin E, where M, E and e are the mean anomaly, eccentric anomaly, and eccentricity, resp. With a few other equations (and a method to solve a transcendental equation), one can use the equation to produce in polar coordinates (r, [itex]\upsilon[/itex]), where nu is the true anomaly, and ultimately from these find the ra and dec of the object. This is fine, but problems poised about the use of the equation seem to give variables like E and e values to derive (r,[itex]\upsilon[/itex]). To make this a practical, real-world, problem, how would one know, say, E and e? Does the equation itself become useful in some other context? Perhaps in the development of orbital elements?