to some landmark that did appear, the so-called "offset aiming points". Finally, the group noted that many of the functions in such a system would overlap formerly separate tools like the navigation systems. They proposed a single system that would offer mapping, navigation, autopilot and bomb aiming, thereby reducing complexity, and especially the needed space. Such a machine first emerged in the form of the AN/APQ-24, and later the "K-System", the AN/APA-59. Through the 1950s and 1960s, radar bombing of this sort was common and the accuracy of the systems were limited to what was needed to support attacks by nuclear weapons – a circular error probable (CEP) of about was considered adequate. As mission range extended to thousands of miles, bombers started incorporating inertial guidance and star trackers to allow accurate navigation when far from land. These systems quickly improved in accuracy, and eventually became accurate enough to handle the bomb dropping without the need for a separate bombsight. This was the case for the accuracy demanded of the B-70 Valkyrie, which lacked any sort of conventional bombsight. Modern systems During the Cold War the weapon of choice was a nuclear one, and accuracy needs were limited. Development of tactical bombing systems, notably the ability to attack point targets with conventional weapons that had been the original goal of the Norden, was not considered seriously. Thus when the US entered the Vietnam War, their weapon of choice was the Douglas A-26 Invader equipped with the Norden. Such a solution was inadequate. At the same time, the ever-increasing power levels of new jet engines led to fighter aircraft with bomb loads similar to heavy bombers of a generation earlier. This generated demand for a new generation of greatly improved bombsights that could be used by a single-crew aircraft and employed in fighter-like tactics, whether high-level, low-level, in a dive towards the target, or during hard maneuvering. A specialist capability for toss bombing also developed in order to allow aircraft to escape the blast radius of their own nuclear weapons, something that required only middling accuracy but a very different trajectory that initially required a dedicated bombsight. As electronics improved, these systems were able to be combined, and then eventually with systems for aiming other weapons. They may be controlled by the pilot directly and provide information through the head-up display or a video display on the instrument panel. The definition