Abstract
Over 1500 lunar laser range measurements have been made during the past six years at McDonald Observatory. These data have been fitted with a 41 cm r. m. s. residual. The geocentric coordinates of McDonald Observatory are now known to better than 1 m, the three-dimensional coordinates of the Moon and the selenocentric coordinates of the retroreflectors are accurate to about 25 m, and the mass ratio Sun/(Earth + Moon) is determined to 2 parts in 107. A search for the Nordtvedt term in the Moon’s orbit, a term predicted by some relativity theories, gives a null value, a result consistent with general relativity. The measurement of the physical librations determines very accurately the moment of inertia parameters β = (C - A)/B and γ = (B - A)/C, and significantly determines the third degree gravitational harmonics C 30 , C 32 , S 32 and S 33 The postfit residuals are not random but yield corrections to the rotation of the Earth, values of U. T. 0 for individual days having typical accuracies of 0.5 ms (20cm). The anticipated regular operation of two or more stations will allow the separation of U. T. 1 and polar motion.
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Schedule a callMore From: Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
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