The Qitai radio telescope

This study presents a general outline of the Qitai radio telescope (QTT) project. Qitai, the site of the telescope, is a county of Xinjiang Uygur Autonomous Region of China, located in the east Tianshan Mountains at an elevation of about 1800 m. The QTT is a fully steerable, Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter. The QTT has adopted an umbrella support, homology-symmetric lightweight design. The main reflector is active so that the deformation caused by gravity can be corrected. The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to 115 GHz. To satisfy the requirements for early scientific goals, the QTT will be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers. A multi-function signal-processing system based on RFSoC and GPU processor chips will be developed. These will enable the QTT to operate in pulsar, spectral line, continuum and Very Long Baseline Interferometer (VLBI) observing modes. Electromagnetic compatibility (EMC) and radio frequency interference (RFI) control techniques are adopted throughout the system design. The QTT will form a world-class observational platform for the detection of low-frequency (nanoHertz) gravitational waves through pulsar timing array (PTA) techniques, pulsar surveys, the discovery of binary black-hole systems, and exploring dark matter and the origin of life in the universe. The QTT will also play an important role in improving the Chinese and international VLBI networks, allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems. Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame. Potentially, the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence.