8/10/2019 Astronomy Coordinate Transformation
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function [ l,b,P ] = co_trans_astro(
alpha,delta,p,alphap,deltap,lp_1 )% CO_TRANS_ASTRO transforms the
coordinate from one system to other.% alpha RA of galaxy in former
coordinate of galaxy% delta DEC of galaxy in former coordinate of
galaxy% p is the position angle in former coordinate system% alphap
is the RA of the north pole of the latter coordinate system where
the coordinate should be transformed% deltap is the DEC of the
north pole of the latter coordinate system% lp_1 is the RA of the
north pole of former coordinate system in terms of latter
coordinate system
% Changing the degrees to radiancon = pi/180;alpha =
con*alpha;delta = con*delta;p = con*p;alphap = alphap*con;deltap =
deltap*con;lp1 = lp*con;lp = lp1 - pi/2
% Defining three eular matricesR_z1 = [cos(-lp),sin(-lp),0;
-sin(-lp),cos(-lp),0;
0,0,1];R_x2 = [1,0,0; 0,cos(pi/2-deltap),sin(pi/2-deltap);
0,-sin(pi/2-deltap),cos(pi/2-deltap)];
R_z2 = [cos(pi/2+alphap),sin(pi/2+alphap),0;
-sin(pi/2+alphap),cos(pi/2+alphap),0; 0,0,1];
%Transformation matrixA_1 = R_z1*R_x2*R_z2;
%Transformed coordinatesA =
A_1*[cos(delta)*cos(alpha);cos(delta)*sin(alpha);sin(delta)];
% A = [cos(b)*cos(l);cos(b)*sin(l);sin(b)]
%value of latitudeb = asin(A(3));
%finding longitudel = atan2(A(2),A(1));if l < 0 l = l +
2*pi;end
%-----------------------------------------------------------%to
change position anglepos = inv(A_1);cosk =
([-sin(delta)*cos(alpha),-sin(delta)*sin(alpha),cos(delta)]*pos)*...
[-sin(b)*cos(l);-sin(b)*sin(l);cos(b)];sink =
([-sin(delta)*cos(alpha),-sin(delta)*sin(alpha),cos(delta)]*pos)*...
[-sin(l);cos(l);0];k = atan2(sink,cosk);if k < 0
