function iss=seasons(jd);
%function iss=seasons(jd);
% returns the indices of the Mass Bay seasons
greg=[1989 12 7 6  0 0;
1990  3 1 0  0 0;
1990  6 1 0  0 0;
1990  9 1 0  0 0;
1990 11 1 0  0 0;
1991  3 1 0  0 0;
1991  6 1 0  0 0;
1991  9 1 0  0 0;
1991 11 1 0  0 0;
1992  3 1 0  0 0;
1992  6 1 0  0 0;
1992  9 1 0  0 0;
1992 11 1 0  0 0;
1993  3 1 0  0 0;
1993  6 1 0  0 0;
1993  9 1 0  0 0;
1993 11 1 0  0 0;
1994 2 27 0  0 0];

[m,n]=size(greg);
for i=1:m,
  iss(i)=tind(jd,greg(i,:));
end
