The 2.5-meter (100-inch) Irénée du Pont telescope has been in operation at Las Campanas Observatory since 1977. The telescope was a result of a gift in 1970 from Mr. and Mrs. Crawford H. Greenewalt to the Carnegie Institution of Washington, which supplied supplemental funds. Basic considerations in designing the telescope were that it be as versatile, reliable, and convenient as possible for its size, and that it have excellent optical performance to match the natural observing conditions offered by the site. Because there were no plans at the time to build companion instruments, such as a large Schmidt for wide-angle surveys, the du Pont telescope was designed to have an exceptionally wide field for direct photography.
