THE OBSERVER’S HANDBOOK for 1968 is the 60th edition. The table of contents has been replaced by an alphabetical listing. It is hoped that this will prove of greater usefulness. Certain changes among the miscellaneous astronomical data have been made in accord with the conversion of the Astronomical Ephemeris and American Ephemeris to the I.A.U. system of astronomical constants. The tenth satellite of Saturn has been added to the table of satellites of the solar system. The times of sunrise and sunset, and of twilight, are again the values for the current year. A table of the objects in Messier’s catalogue has been added.
During 1968 the range of the moon’s declination is approaching its greatest value, so that the moon occults stars of the Pleiades. Jupiter, Saturn and the stars Antares and Spica are also occulted this year (p. 64). The asteroid Icarus approaches closest to the earth on June 15 (p. 69).
Cordial thanks are offered to all individuals who assisted in the preparation of this edition, to those whose names appear in the various sections and to David Crampton, Barbara Gaizauskas, Gretchen Hagen, Helen Sawyer Hogg, David Lindop, Eleanor Parmenter, Michael Scherk, Maude Town and Isabel William son. Special thanks are extended to Margaret W. Mayall, Director of the A.A.V.S.O., for the predictions of Algol and the variable stars and to Gordon E. Taylor and the British Astronomical Association for the prediction of planetary appulses and occultations.
My deep indebtedness to the British Nautical Almanac Office and to the American Ephemeris is gratefully acknowledged.
Ruth J. Northcott
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