WEIZAC, Israel's first locally built electronic computer - which was designed and constructed at the Weizmann Institute of Science in Rehovot 52 years ago - will be recognized on Tuesday as a "Milestone in International Computing History" by the Institute of Electrical and Electronics Engineers. The first computer's builders will be honored with a "WEIZAC" medal presented at a special ceremony by Weizmann Institute president Prof. Daniel Zajfman. WEIZAC was not only Israel's first electronic computer but also one of the first in the world. After being launched in 1954, it functioned on the Rehovot campus until the early 1960s. It was used for mathematical research that entailed complex calculations that could not easily be performed manually. One set of early computations enabled scientists to chart maps giving a very close approximation of high and low tide fluctuations throughout the world and predict the precise location of the point in the Atlantic at which high and low tides never occur - a prediction later confirmed by measurement. In another study, Weizmann scientists used it to calculate the spectrum of a helium atom. Solving the dynamic relationships between the three particles making up the atom is considered a highly complex mathematical task, and despite the development of modern, powerful computers, there is still no general, complete solution to such problems. Two successors to WEIZAC - GOLEM I (1964) and GOLEM II (1972), which were also designed and constructed at the institute, were innovative and extremely advanced in their class. They were used for research at the institute and by scientists from other Israeli research centers. In one area, the GOLEM I held a world record: It was capable of handling words 75 bits long, which was longer than the words any other computers at that time could hold.