A simple active corrector for liquid mirror telescopes observing at large zenith angles

We investigate a corrector system, having a single spherical active secondary, that compensates the large aberrations of a liquid mirror observing at large angles from the zenith. This simple system gives subarcsecond images in small subregions within a 20 degree field. Although the performance is insufficient for imagery, it would be useful for high-resolution spectroscopy of compact objects. Adding adaptive optics to the system would greatly improve its performance, extending its accessible field and rendering it useful for high-resolution imagery