Surface adjustment of the IRAM 30 m radio telescope

The techniques used to set and stabilise the surface of the IRAM 30 m radio telescope to a final root mean square accuracy of about 50 µm are described. This involved both phase retrieval and phase coherent holography using a variety of radiation sources at several frequencies. A finite-element model was utilised in improving the temperature control system for the telescope structure. The factors influencing the ultimate surface accuracy are discussed.