Optimization of focusing optics of RATAN-600 radio telescope

Results of simulations of RATAN-600 radio telescope focusing optics are given. It is shown that due to suboptimal shape of the secondary mirror, the total energy loss amounts to 10%÷15% at low elevations and 2÷4% at high elevations. New ways of focusing optics optimization, which allow to compensate for up to 80% of the energy loss caused by the non-optimal shape of the secondary mirror, are proposed. The proposed solutions were verified by extensive simulations. These simulations used geometrical optics approximation (GO), supplemented by the calculation of the near and the far field with projected aperture (PA) and physical optics (PO) methods, thus taking the finite wavelength effects into account.