Wide-field tracking with zenith-pointing telescopes

Equipped with a suitable optical relay system, telescopes employing low-cost fixed primary mirrors could point and track while delivering high-quality images to a fixed location. Such an optical tracking system would enable liquid-mirror telescopes to access a large area of sky and employ infrared detectors and adaptive optics. Such telescopes could also form the elements of an array in which light is combined either incoherently or interferometrically. Tracking of an extended field requires correction of all aberrations including distortion, field curvature and tilt. A specific design is developed that allows a 10-metre liquid-mirror telescope to track objects for as long as 30 minutes and to point as far as 4 degrees from the zenith, delivering a distortionfree diffraction-limited image to a stationary detector, spectrograph, or interferometric beam combiner.