A comparison of Brown's Lunar Tables with the theory from which they were constructed.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A comparison of Brown's Lunar Tables with the theory from which they were constructed. Woolard, Edgar W. Abstract For 6o dates at half-day intervals, from 1948 April 24.0 to May 24.0 UT, the longitude and latitude of the moon to two decimals of a second of arc and the parallax to three decimals were taken from Brown's tables and compared with values that had been computed to 5 decimals directly from Bro~n's theoretical expressions by the Selective Sequence Electronic Computer of International Business Machines Corporation. Significant differences between the SSEC and the tabular values were evident in the longitude and in the latitude. The discrepancy in the longitude is very small but is systematic, the principal part apparently having a period of about a month, with an amplitude of the order of 0'.' 1; the discrepancy in the latitude is strongly periodic, with an amplitude about 0'.' 15 and a period about a month. An analysis of these differences to determine their source appeared advisable. The SSEC computations were therefore compared in detail with the tabular computations for the longitude on 14 selected dates, and for the latitude on 12 of these dates. The differences are for the most part satisfactorily accounted for by approximations and expedients adopted by Brown and iledrick in the construction of the tables to facilitate their practical use, and are within the standards of accuracy that were set for the tables. The large discrepancy in the latitude, however, is principally due to an oversight in the tables; in constructing the tables, the effect of the long period variations of the lunar inclination upon several of the large terms in the latitude was inadvertently included twice. The resulting error in the tabular latitude is large enough to be detected in observations; it has been found in a comparison of the tabular latitude with the observed latitude obtained with the 6-inch transit circle at the IT. S. Naval Observatory during 1929-I 949. U.S. Naval Observatory, Washington, D. C. Publication: The Astronomical Journal Pub Date: April 1952 DOI: 10.1086/106651 Bibcode: 1952AJ.....57Q..31W full text sources ADS |