the observer’s handbook for 1971 is the 63rd edition. A number of small changes and additions have been made in response to suggestions from readers; further changes and additions are contemplated for the 1972 edition. Additional informa­tion about the planet Mars is included, in view of the favourable opposition which occurs in 1971.

the observer’s handbook for 1970 is the 62nd edition. The time zone map has been supplied courtesy of the Department of Energy, Mines and Resources of Canada. The sections on Nearest Stars, Galactic Nebulae and Radio Sources have been rewritten.

THE OBSERVER’S HANDBOOK for 1969 is the 61st edition. The time zone map has been revised and supplied courtesy of the Department of Energy, Mines and Resources. A table giving the longitude of the central meridian of Mars has been added. Changes have been made in the table of Saturn’s satellites, so that it will be more useful to observers. The times of sunrise and sunset, and of twilight, are again for the current year. The magnitudes in the table of Messier’s objects have been revised.

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 The table of contents has been replaced by an alphabetical listing.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.