c program to get a sinewave for light curve modeling
              real t0,p,a
              open(unit=10,file='sine.dat',status='unknown')
              print*,'Enter starting time:'
              read*,t0
              print*,'Enter stop time:'
              read*,t1
              print*,'Enter sine period:'
              read*,p
              print*,'Enter peak-to-peak amplitude:'
              read*,a
              cycles=(t1-t0)/p
              n=int(cycles*360)
              ts=-1.0
              print*,'n=',n,' cycles=',cycles
              do i=1,n+1
              t=ts+i
              f=a*sin(t/57.3)
c              print*,i,p*t/360,f
              write(10,*)p*t/360.0+t0,f
              enddo
              stop
              end