rotationsx.py 文件源码

def cvt_v2v3_using_body2inertial_Q_to_c1c2pa_tuple(Q,v2,v3):
   """Given Q and v2,v3 gives pos on sky and V3 PA """
   Vp_body = Vector(0.,0.,0.)
   Vp_body.set_xyz_from_angs(v2,v3)
   Vp_eci_pt = Q.cnvrt(Vp_body)
   coord1  = atan2(Vp_eci_pt.y,Vp_eci_pt.x)
   if coord1 < 0. : coord1 += PI2
   coord2 = asin(unit_limit(Vp_eci_pt.z))

   V3_body = Vector(0.,0.,1.)
   V3_eci_pt = Q.cnvrt(V3_body)
   NP_eci = Vector(0.,0.,1.)
   V_left = cross(NP_eci,Vp_eci_pt)
   if V_left.length()>0.:
      V_left = V_left/V_left.length()
   NP_in_plane = cross(Vp_eci_pt,V_left)
   x = dot(V3_eci_pt,NP_in_plane)
   y = dot(V3_eci_pt,V_left)
   pa  = atan2(y,x)
   if pa < 0. : pa += PI2

   return (coord1,coord2,pa)