Hydrostatic bearings for the World's great telescopes

摘要

Hydrostatic load bearing, the technique of moving a great load on a pad of pressurized oil, was probably first demonstrated as an amusing phenomenon at the Paris Industrial Exposition of 1878 in a purposeless device labeled 'Le Chemin de For de Glace' (The Ice Railway). Seventy years later the principles were objectively revived and improved for application to the problems attending the drives to machine tool slides and the slow moving bearings encountered in telescope engineering. Today, no large telescope is planned without taking advantage of the phenomenal improvement over conventional types that is afforded by these bearings. This article reviews the historical background; and then discusses basic principles, some of the control systems available and current applications. In conclusion, it mentions possible future developments.