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