The spreadsheet ld_comp.xls allows the calculation of the center-to-center (i.e. no semidiameter) geocentric lunar distance (cells A10, B10, C10) from almanac data (row 2). The topocentric result in cells D10, E10, F10 includes the effect of Moon’s parallax on the lunar distance, when observed from an assumed position (cells E6, F6). While these results do not include the effects of refraction, they are close enough for your sextant to be preset to an angle that is sufficiently close to the actual observed value. The values are preset for a Sun lunar on January 8, 2011, UT = 22:00:00.

Summary for spreadsheet ld_prec.xls:

Input cells: A2, B2, C2, E2, F2, E6, F6

Output cells: A10, B10, C10, D10, E10, F10