Determination of Coordinates for the Orroral Lunar Ranging Station
Using models of the Earth-Moon system developed from analysis of 10 years of laser ranging observations from the McDonald Observatory, we have analyzed observations obtained by the Orroral Lunar Ranging Station since April 1978. Normal point residuals from many of the observations performed before April 1980 using a 20 ns, multiple-mode laser pulse are discreetly spaced, as multiples of 6 ns, and may have been corrupted by variations in pulse shape. Further evaluation is required before these observations are used in scientific analyses. Observations performed during the MERIT Short Campaign (August — October 1980) using a 6 ns, single-mode pulse are apparently reliable. Using 27 single photoelectron events, obtained on 7 nights during this period, we have estimated the coordinates of Orroral, with respect to McDonald, with uncertainties of 1–2 m in cylindrical radius and longitude and 5–10 m in z-axis distance.
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