/* ------------------------------------------
    GeodesicViewer
    
    "Periodic orbits in the Schwarzschild spacetime"
    J.Levin and G. Perez-Giz, Phys. Rev. D 77, 103005 (2008).
    
    Thomas Mueller, Frank Grave
    Visualization Research Center (VISUS)
    University of Stuttgart  
    
    Use with wxmaxima:
       batchload("periodicOrbits.wxm")
   ------------------------------------------ */

/* velocity */
b(rs,E,r):=sqrt(1-(1-rs/r)/E^2);

/* angle */
ksi(rs,E,L,r):=float(asin(L/r/sqrt(E^2/(1-rs/r)-1))/%pi*180);