Parkes Counterweight Issues May 4, 2002 1 Background It became clear, during the course of the study of the windloading on the Parkes reflector (ref: AT/39.3/113) that the counterweight was not optimally fulfilling its function. ... Figure 1: The elevation motor currents as a function of the elevation. ... If the weight is positioned below the current centre of mass (32 cm south of the elevation axis), then the horizon current doubles to 8 A; the peak current (at El0 increases by 0.3%. ...

metrologia The leap second: its history and possible future R. A. Nelson, D. D. McCarthy , S. Malys, J. Levine, B. Guinot, H. F. Fliegel , R. L. Beard and T. R. Bartholome w Abstract. This paper reviews the theoretica l motivatio n for the leap second in the context of the historica l evolutio n of time measurement . Th e periodic insertio n of a leap second step into th e scale of Coordinate d Universal Time (UTC) necessitates frequent changes in comple x timekeepin g systems an d is currentl y th e