the observer’s handbook for 1980 is the seventy-second edition. I thank all those who have contributed to its production: those listed on the inside front cover, and also my editorial assistants Tim Pointing and Douglas Welch.

I also thank all those who have sent me corrections to and suggestions about the handbook. Errors inevitably creep in; if you see one please let me know, obvious though it may be.

Special thanks are due to Dr. Helen Hogg for her interest and her helpful com­ ments, and to Ian McGregor for previewing the 1980 sky for me in the Star Theatre of the McLaughlin Planetarium. I am also grateful to Terence Dickinson for sug­gesting - and executing - the reorganization of the material on the planets. As always, the members of the R.A.S.C. National Council, the editor Dr. Lloyd Higgs and the executive secretary Rosemary Freeman have given me their cheerful support and assistance. The handbook also benefits from the direct and indirect support of the David Dunlap Observatory and Erindale College, University of Toronto.

The handbook is particularly indebted to H.M. Nautical Almanac Office and to the American Ephemeris for the generous contribution of essential material. Special thanks go to Leslie V. Morrison and the Occultation Section of H.M.N.A.O. for providing the wealth of material on total and grazing lunar occultations.

I hope that the observer’s handbook helps you to find the pleasure and satisfac­ tion which astronomy can provide. Good observing!

John R.Percy