Accession Number : ADA528116


Title :   Computation of the Quantities Describing the Lunar Librations in the Astronomical Almanac


Descriptive Note : Technical note no. 74


Corporate Author : NAVAL OBSERVATORY WASHINGTON DC


Personal Author(s) : Taylor, D B ; Bell, S A ; Hilton, J L ; Sinclair, A T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a528116.pdf


Report Date : Aug 2010


Pagination or Media Count : 11


Abstract : Lunar physical ephemerides, tabulated daily including llbration, can be found in Section D of The Astronomical Almanac (AsA). This technical note describes the method used for calculating the lunar librations and other quantities on the odd pages D7-D21 of the AsA with effect from the 2011 edition. Prior to the 1985 edition, formulae and constants for the physical ephemeris of the Moon were due to Hayn (1907). Beginning with the 1985 edition, librations have been generated using the analytical theory of Eckhardt (1981, 1982). Since the inclusion of a rotational ephemeris for the Moon given in the form of three Euler angles in the JPL lunar ephemerides starting with DE403/LE403, Standish et al. (1995), it has been a long-standing goal to implement these ephemerides in the calculation of lunar librations and improve the quality of the tabulated physical ephemerides of the Moon in Section D. Work started by Hilton (2004) on interpreting these ephemerides has paved the way to the work presented here which describes the calculation of librations and related quantities as they have been implemented starting with the 2011 edition of the AsA.


Descriptors :   *ALMANACS , *NAUTICAL , *ASTRONOMY , *LUNAR ENVIRONMENTS , EPHEMERIDES , QUANTITY , COMPUTATIONS , ALGORITHMS , HYDROGRAPHY


Subject Categories : Astronomy
      Astrophysics
      Marine Engineering


Distribution Statement : APPROVED FOR PUBLIC RELEASE