double precision PV(6)
integer res
double precision jd0
double precision dt1, dt2

jd0 = 2442457
dt  = 0.5D0
dt2 = 0.9D0

res = f90calceph_sopen("example1.dat")
if (res.eq.1) then

   ! the heliocentric coordinates of Mars
   res = f90calceph_scompute(jd0, dt1, 4, 11, PV)
   write (*,*) PV

   res = f90calceph_scompute(jd0, dt2, 4, 11, PV)
   write (*,*) PV

  call f90calceph_sclose
endif