code: def bb(self,*args,**kwargs):
          
          _check_roSet(self,kwargs,'bb')
          lbd= self._lbd(*args,**kwargs)
          return lbd[:,1]
docs: NAME:
             bb
          PURPOSE:
             return Galactic latitude
          INPUT:
             t - (optional) time at which to get bb
             obs=[X,Y,Z] - (optional) position of observer (in kpc) 
                           (default=Object-wide default)
                           OR Orbit object that corresponds to the orbit
                           of the observer
                           Y is ignored and always assumed to be zero
             ro= distance in kpc corresponding to R=1. (default=Object-wide default)         
          OUTPUT:
             b(t)
          HISTORY:
             2011-02-23 - Written - Bovy (NYU)