C+
C NAME:
C	EqKeplerd
C PURPOSE:
C	Kepler's equation is used in the determination of orbital positions.
C	It gives the relation between mean and eccentric anomaly (for given
C	orbit eccentricity).
C CATEGORY:
C	Celestial mechanics
C CALLING SEQUENCE:
	function EqKeplerd(E)
C INPUTS:
C	E		double precision	eccentric anomaly (degrees)
C	M		double precision	mean anomaly (degrees)
C	ee		double precision	orbit ellipticity (eccentricity)
C OUTPUTS:
C	EqKepler	double precision	fnc value
C INCLUDE:
	include		'math.h'
C EXPLICIT:
	double precision	ee
	double precision	M
C COMMON BLOCKS:
	common 	/KEPLERD/	M,ee
C PROCEDURE:
C	The eccentric anomaly is the root of Kepler's equation:
C	EqKepler = X-(180/PI)*ee*sin(X)-M = 0
C	See O. Montenbruck, "Practical Ephemeris Calculations", Springer 
C	(1989), par. 3.1.1.4, p. 44
C MODIFICATION HISTORY:
C	JAN-2004, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
C-
	    double precision	E

	double precision	dsind

	if (ee .lt. 1.0d0) then
	    EqKeplerd = E-MATH__DPR*ee*dsind(E          )-M
	else
	    EqKeplerd = E-MATH__DPR*ee*dsinh(E*MATH__RPD)+M
	end if

	return
	end