PREFACE

The Handbook for 1947 is the 39th issue. The chief improvement in it is the inclusion again of Dr. P. M. Millman’s portion on Meteors.

Four circular star maps 9 inches in diameter at a price of one cent each, and a set of four maps plotted on equatorial co-ordinates at a price of ten cents, are obtainable from the Director of University Extension, University of Toronto, Toronto 5.

Celestial distances given herein are based on the standard value 8".80 for the sun’s parallax rather than the more recent value 8".790 as determined by Sir Harold Jones. The predictions of the minima of Algol are based on a period of 2.867318 days by W. M. Smart, and from a minimum at J. D. 2,429,234.6859 observed by J. S. Hall. Observations of three minima by D. W. Rosebrough in November 1945, confirmed the Handbook predictions within about 3 minutes. Our deep indebtedness to the British Nautical Almanac and the American Ephemeris is thankfully acknowledged.

Dr. F. S. Hogg, the Assistant Editor, as in recent years, assumed the responsibility of preparing this volume and to him the chief credit of its success is due; but sincere thanks are tendered to all those names mentioned in the book. It is gratifying to see the Handbook attain so wide a circulation.

David Dunlap Observatory,         C. A. Chant.
Richmond Hill, Ont., October 1946.