subroutine recons(n,phi,x,y,xst,yst,dcut)
*     given (phi, sa), reconstruct the curve and give (x,y)
*     note theta = phi + alpha   (0 < alpha < 2 pi)
      integer j,n
      double precision phi(0:8192),x(0:8192),y(0:8192)
      double precision tx(0:8192),ty(0:8192)
      double precision h,hp,ad,xst,yst,xclose,yclose,sa,pi,p2,
     +                 hp2,dcut,theta
      common/salpha/sa
      common/gridsz/h,hp
      common/valupi/pi,p2

      hp2 = 2.D0*hp
      call kfilter(n,dcut,phi)

      do 10 j=0,n
         x(j) = 0.D0
         y(j) = 0.D0
         theta = phi(j) + dble(j)*hp2
         tx(j) = sa*dcos(theta)
         ty(j) = sa*dsin(theta)
 10   continue

      call fin2(N,h,p2,x,tx)
      call fin2(N,h,p2,y,ty)

      xclose = x(n)
      yclose = y(n)

      do 20 j=0,n
         ad = dble(j)*h
         x(j) = xst + x(j) - ad*xclose
         y(j) = yst + y(j) - ad*yclose
 20   continue

      call kfilter(n,dcut,x)
      call kfilter(n,dcut,y)

      end