;+ ;FUNCTION: pangle,theta,phi,b_theta,b_phi ;PURPOSE: ; Computes pitch angle given two sets of theta and phi ;INPUT: ; theta,phi: double (array or scaler) first directions ; b_theta,b_phi : double (array or scaler) second directions ;RETURNS: pitch angle (array or scaler) same dimensions as theta and phi ; ;CREATED BY: Davin Larson ;LAST MODIFICATION: @(#)pangle.pro 1.4 95/11/28 ; ;- function pangle, theta,phi,b_theta,b_phi,vec = vec if n_elements(vec) eq 3 then xyz_to_polar,vec,theta=b_theta,phi=b_phi sphere_to_cart,1.,b_theta,b_phi,bx,by,bz sphere_to_cart,1., theta, phi,sx,sy,sz dot = (bx*sx + by*sy + bz*sz) pa = 180./!dpi*acos(dot) return, pa end