Large Zenith Telescope
The Large Zenith Telescope (LZT) is a 6.0 m diameter liquid mirror telescope located in the University of British Columbia's Malcolm Knapp Research Forest, about 70 km (43 mi) east of Vancouver. It is one of the largest optical telescopes in the world, but still quite inexpensive. The telescope was completed in the spring of 2003.
While a zenith telescope has the obvious disadvantage of not being able to look anywhere but at a small spot straight up, its simplified setup permits the use of a mirror consisting of a smoothly spinning pan filled with copper mercury. Such a mirror can be made much larger than a conventional mirror, greatly increasing light collecting ability. The LZT is used for transit imaging, meaning that earth's rotation moves stars along the sensor, and the latent image in the sensor is moved electronically in step with this movement and read out at the trailing edge.
The telescope made use of parts from the three-meter diameter NASA Orbital Debris Observatory telescope, which had been using a liquid mercury mirror for several years.