On Tue, Oct 11, 2011 at 4:06 PM, Anthony Jackson <[email protected]> wrote: > On 10/11/2011 5:34 AM, Captain Joy wrote: > >> No, but the angle a planet moves through given its current location >> on the ellipse, semi major axis, delta-T, and eccentricity is an >> equation that can be looked up. > > Actually, it isn't. There's no simple method of computing that, at least > accurately when delta-T is a significant fraction of the orbital period.
Sure there are. There's no closed form, but there are iterative methods that will produce a result with arbitrary accuracy. There are libraries to do that in just about any reasonable programing language (and some unreasonable ones, like Common Lisp and javascript.) you would care to write a program in. Modern computation makes many hard problems easy with a little bit of brute force. (Though Maple did a fine job solving Kepler's equation via Newton's method when I was in college, so it's not a problem that really requires a whole lot of computational brute force.) -- David Scheidt [email protected] _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
