c****************************************************************

	real*8 function fc(r_tsp)

       	implicit none

c	INPUT VARIABLES:
        real*8 r_tsp               !time since periapsis
	real*8 tpv(3)
        real*8 pos(3)
        real*8 vel(3)
        real*8 los_v(3)

c   	OUTPUT VARIABLES: none

c	LOCAL VARIABLES:
        real*8 r_sc_look, r_sc_az, r_az
	common /sc_point/ r_sc_look, r_sc_az
	common /target/ tpv

	call orrmread1(16,r_tsp,pos,vel,0)
	call lincomb(-1.d0,pos,1.d0,tpv,los_v)
	call getangs(pos,vel,los_v,r_az,r_sc_look)
	fc = r_az - r_sc_az
	return

        end