on error 
if (&1major.eq.0) then 
  say "No clean beam, flux density estimate impossible" 
  return 
endif 
define double theta[2] k lambda nu jyperk 
let nu &1restfre 
let theta &1major &1minor 
let theta theta|2.|sqrt(log(2.0)) 
let lambda 2.99792458e8|nu*1e-6 
let jyperk 2.0*1.38e3*pi*theta[1]*theta[2]|lambda^2 
say " K per Jy : " '1|jyperk' 
say "mJy per K : " '1e3*jyperk'