In use on large telescopes only since the 1990s, adaptive optics is now considered almost indispensible for imaging distant objects. The technology is developing rapidly and will soon expand into the next generation of large telescopes. Meanwhile, work is underway to apply AO concepts to other areas.
The famous 200-inch Hale Telescope at Mount Palomar, California, installed adaptive optics in 1999. The 241-actuator system will soon be upgraded with the PALM-3000, an "extreme adaptive optics" system with 3,388 actuators. Researchers predict the system will allow the Hale Telescope to equal the performance of a 5-meter telescope in space.
A more recent development in adaptive optics for telescopes is the laser guide star, which acts as a wavefront reference source when bright enough stars are not present in a region of the sky.
The Palomar Observatory is owned and operated by the California Institute of Technology.
Robert Tyson, professor at University of North Carolina at Charlotte and author of five books on adaptive optics, introduces the topic and explains the laser guide star in this video. Implementation of the adaptive optics upgrade to the Hale Telescope at Mount Palomar is discussed by two researchers from Caltech, Antonin Bouchez and Christoph Baranec.
Palomar's 200-inch telescope: still innovating after 60 years of science (SPIE Newsroom)
Palomar Observatory website
Unique Sky Survey Brings New Objects into Focus (Caltech press release)
Status of the PALM-3000 high-order adaptive optics system by Antonin H. Bouchez, Richard G. Dekany, John R. Angione, Christoph Baranec, Khanh Bui, Rick S. Burruss, Justin R. Crepp, Ernest E. Croner, John L. Cromer, Stephen R. Guiwits, David D. S. Hale, John R. Henning, Dean Palmer, Jennifer E. Roberts, Mitchell Troy, Tuan N. Truong, and Jeffry Zolkower (2009 paper in SPIE Digital Library -- open access)
SPIE-published books by Robert K. Tyson:
Introduction to Adaptive Optics (2000)
Field Guide to Adaptive Optics (Tyson and Frazier, 2004)
The Lighter Side of Adaptive Optics (2009)