in the book SETI 2020 that revisits the conclusions of the Cyclops report. Particular differences include: Points 4 and 5: Cyclops preferred the low end of the microwave band. With technology advances, the disadvantages of higher frequencies are smaller, and they have other advantages. Anything from microwave to optical looks roughly equivalent. Point 6: The highest frequency of such an array can, and should be, much higher. Point 8: Beacons will probably be pointed, and not omnidirectional. Modern processing power makes this possible, and it is much more energy efficient. Point 9: Although not called out in SETI 2020, the point "Beacons ... will surely be highly monochromatic," has suffered substantial criticism. As Earth's communication technology moves toward spread spectrum signals, SETI observations are being augmented with searches for high bandwidth signals. Furthermore, there are now proposals for beacons that are almost as easy to detect as monochromatic signals, but can contain information as well. Point 10: The optical processing of Cyclops should be replaced by digital signal processing. Current availability In the 1970s, 10,000 copies of the Cyclops report were distributed by NASA. It is reasonable to assume that most major figures within the current SETI community have seen the document. As of the 1990s, the Cyclops report had long been out of print. In 1995 The SETI League collaborated with the SETI Institute to reprint this important historical document. Project Cyclops, Second Printing, is currently available through The SETI League. It went on sale in June, 1996, honoring the 25th anniversary of the opening Project Cyclops meeting. John Billingham, who co-chaired the Cyclops team, wrote a dedication to Bernard M. Oliver, which appears in the new edition, along with introductory remarks by SETI League president Richard Factor and executive director H. Paul Shuch. In the 2000s, NASA digitized the original report and made it available on-line at no cost. See also SETI Square Kilometre Array Project Phoenix Isotropic beacon References External links A Brief SETI Chronology The background to SETI and Project Phoenix Optical SETI references in Project Cyclops document Extraterrestrial life Search for extraterrestrial intelligence Spaceflight