Angular error of position of RATAN-600 screens during radial displacement

The accuracy of the main mirror of the RATAN-600 radiotelescope is determined primarily by the accuracy of manufacture of the surface of the reflecting elements and their placement in their calculated positions in radius, azimuth, elevation angle and altitude. Study of the azimuth and elevation angle errors arising upon radial displacement of the screen was a necessary element in combined studies of the radiotelescope performed in order to increase its effectiveness. The studies were performed using 23 screens from the central group of the north sector of the circular reflector. Measurements were performed by an autocollimation theodolite using 80 mm diameter mirror in six fixed positions on two different occasions. Each session included measurements with the screens moving forward and back. The major results indicate that in spite of measurable errors in manufacture and installation of the rails of the supporting beam and carriage rollers, their influence on accuracy of the surface of the circular reflector of the radiotelescope can be reduced to the necessary level. Proper consideration of azimuthal errors is effective for wavelengths of over 4 mm.