OBSERVER'S HANDBOOK 1984 EDITOR: ROY L. BISHOP THE ROYAL ASTRONOMICAL SOCIETY OF CANADA CONTRIBUTORS AND ADVISORS Alan H. Batten, Dominion Astrophysical Observatory, Victoria, BC, Canada V8X 4M6 (The Nearest Stars). Roy L. Bishop, Department of Physics, Acadia University, Wolfville, NS, Canada B0P 1X0 (Editor). Terence Dickinson, R.R. 3, Odessa, ON, Canada K0H 2H0, (The Planets). D a v id W. D u n h a m , International Occultation Timing Association, P.O. Box 7488, Silver Spring, MD 20907, U.S.A. (Lunar and Planetary Occultations). Alan Dyer, Queen Elizabeth Planetarium, 10004-104 Ave., Edmonton, AB, Canada T5J 0K 1 (Messier Catalogue, Deep-Sky Objects). Fred Espenak, Infrared and Radio Astronomy Branch, NASA-Goddard Space Flight Centre, Greenbelt, MD, U.S.A. 20771 (Eclipses). Marie Fidler, The Royal Astronomical Society of Canada, 136 Dupont St., Toronto, ON, Canada M5R 1V2 (Observatories and Planetaria). Victor Gaizauskas, Herzberg Institute of Astrophysics, National Research Council, Ottawa, ON, Canada K1A 0R6 (Solar Activity). John A. Galt, Dominion Radio Astrophysical Observatory, Penticton, BC, Canada V2A 6K3 (Radio Sources). Robert F. Garrison, David Dunlap Observatory, University of Toronto, Richmond Hill, ON, Canada L4C 4Y6 (The Brightest Stars). Ian Halliday, Herzberg Institute of Astrophysics, National Research Council, Ottawa, ON, Canada K1A 0R6 (Miscellaneous Astronomical Data). William Herbst, Van Vleck Observatory, Wesleyan University, Middletown, CT, U.S.A. 06457 (Galactic Nebulae). Helen S. Hogg, David Dunlap Observatory, University of Toronto, Richmond Hill, ON, Canada L4C 4Y6 (Foreword). Yoshio Kubo, International Lunar Occultation Centre, Astronomical Division, Hydrographic Department, Tsukiji-5, Chuo-ku, Tokyo, 104 Japan (Total and Grazing Lunar Occultations). Barry F. Madore, David Dunlap Observatory, University of Toronto, Richmond Hill, ON, Canada L4C 4Y6 (Galaxies). Brian G. Marsden, Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA, U.S.A. 02138 (Comets, Asteroids). Janet A. Mattei, American Association of Variable Star Observers, 187 Concord Ave., Cambridge, MA, U.S.A. 02138 (Variable Stars). Peter M. Millman, Herzberg Institute of Astrophysics, National Research Council, Ottawa, ON, Canada K1A 0R6 (Meteors, Fireballs and Meteorites). Anthony F. J. Moffat, Departement de Physique, Universite de Montreal, Montreal, PQ, Canada H3C 3J7 (Star Clusters). John R. Percy, Erindale College and Department of Astronomy, University of Toronto, Toronto, ON, Canada M5S 1A7 (Sky Month by Month). P. Blyth Robertson, Earth Physics Branch, Energy, Mines and Resources Canada, Ottawa, ON, Canada K1A 0Y3 (Meteorite Impact Sites). Gordon E. Taylor, H.M. Nautical Almanac Office, Royal Greenwich Observa­ tory, Herstmonceux Castle, Hailsham, East Sussex, England BN27 1RP (Plane­ tary Appulses and Occultations). Joseph F. Veverka, Department of Astronomy, Cornell University, Ithaca, NY, U.S.A. 14853 (Planetary Satellites). Charles E. Worley, U.S. Naval Observatory, Washington, DC, U.S.A. 20390 (Double Stars). PRINTED IN CANADA BY THE UNIVERSITY OF TORONTO PRESS OBSERVER’S HANDBOOK 1984 EDITOR ROY L. BISHOP SEVENTY-SIXTH YEAR OF PUBLICATION © THE ROYAL ASTRONOMICAL SOCIETY OF CANADA 136 DUPONT STREET, TORONTO, ONTARIO M5R 1V2 ISSN 0080-4193 THE ORIGINS OF THE ROYAL ASTRONOMICAL SOCIETY OF CANADA In the mid-nineteenth century, in the bustling Lake Ontario port city of Toronto, there were no professional astronomers. However, many inhabitants of the city were keenly interested in sciences and current developments in them. King’s College, which grew into the University of Toronto, had been started in 1842. In 1849 it had 36 undergraduates attending, and had graduated a total of 55 students in the three faculties of arts, law and medicine. The Toronto Magnetic Observatory had been established in 1840. Its early directors and observers were officers and soldiers in garrison. Some of them, such as Captain J. F. Lefroy, contributed much to the cul­ tural life of the city. Out of this body of interest came the Canadian Institute estab­ lished in 1849 “to promote those pursuits which are calculated to refine and exalt a people”. Besides holding weekly meetings, the Canadian Institute accumulated an out­ standing library. There many hours were spent in study by Andrew Elvins who had come to Canada from Cornwall in 1844. In 1860 he moved to Toronto, with a population then of 44 000, and became chief cutter in a well known clothing store on King Street. While the Canadian Institute held discussion meetings of all sciences, Elvins wished to concentrate on astronomy. For this purpose he gathered together a few like-minded friends. On December 1, 1868 The Toronto Astronomical Club met for the first time, at the Elvins’ home, “having for its object the aiding of each other in the pursuit of astronomical knowledge”. The thousands of meteor sightings of the Leonid showers made in Toronto in November 1867 and 1868 had doubtless encouraged the project. In May, 1869 the word “Club” was changed to “Society”. Written records were kept for the first year, until the secretary moved away. After that, the group met only sporadically, but by the distribution of materials Elvins kept interest alive. As the century wore on, Elvins, who lived till 1918, acquired more kindred spirits, some of them influential and prominent. As a result, on March 10,1890 the organiza­ tion was incorporated as The Astronomical and Astrophysical Society of Toronto. In May, 1900 chiefly through the efforts of one of the important early members George E. Lumsden, the name was changed to The Toronto Astronomical Society. On March 3, 1903 through legal application the name took on its current form, The Royal Astronomical Society of Canada. For many years the Society had its offices and library in the Canadian Institute buildings, and held meetings there. Early in the 1890’s, Dr. Clarence A. Chant of the University of Toronto became deeply interested in the Society. The impetus which he gave to it until his death in 1956 still lingers. During its first fifteen years the Society published annually volumes containing its Transactions and Annual Report. In 1907 Dr. Chant started The Journal of the Royal Astronomical Society of Canada, and this Handbook, called then “The Canadian Astronomical Handbook”. It is a remarkable fact that at the time of his death Dr. Chant had been the Editor of both the Journal and the Hand­ book for exactly 50 years. During this period he received generous assistance from many of the Society’s members. At times the Journal was published monthly, but currently it is bi-monthly. The change of name in 1903 led immediately to the concept that the Society should not be limited to Toronto, but should become national in scope. The second Centre to be established was that of Ottawa in 1906, where the Dominion Observa­ tory was being established. Now the Society has 20 Centres from sea to sea across Canada, as listed elsewhere in this Handbook. The growth in membership to nearly 3000 also shows its flourishing state. H e l e n S a w y e r H o g g 2 EDITOR’S COMMENTS On behalf of The Royal Astronomical Society of Canada, I wish to thank the con­ tributors to the 1984 o b s e r v e r ’s h a n d b o o k (see the inside front cover). In particular I wish to welcome Fred Espenak (Eclipses), Robert Garrison (The Brightest Stars), and William Herbst (Galactic Nebulae) as new contributors. The latter two replace Donald MacRae (David Dunlap Observatory) and Rene Racine (Canada-France- Hawaii Telescope) respectively, both of whom have provided valuable support to the h a n d b o o k over several years. Several revisions and additions have been made for 1984. The table of physical elements of the solar system has been updated using the IAU (1976) system of astronomical constants (U.S. Naval Observatory Circular #163). Joseph Veverka has expanded the table on planetary satellites. The section on time has been revised, partly in response to the introduction of Terrestrial Dynamical Time in 1984. Thanks to the initiative of Fred Espenak, the section on eclipses has been considerably expanded. The magnitude limit for total lunar occultation predictions has again been changed (from 6.0 to 5.0) in recognition of the availability of more extensive predic­ tions for experienced observers from other sources, and to give more emphasis to lunar graze events. Blyth Robertson has revised the section on meteorite impact sites. Janet Mattei has again provided new material for the variable stars section; this year it includes a description of the photoelectric photometry observing program of the AAVSO. Anthony Moffat has included some information on stellar associa­ tions in the star clusters section. William Herbst has revised the list of galactic nebulae to include more objects in the southern sky. In addition to the regular contributors, several other individuals have provided ideas and support. I particularly want to thank Randall Brooks (St. Mary’s Univer­ sity) for providing twilight times, information on an occultation by Neptune, and the base map for the path of Pluto. Leo Enright (Sharbot Lake, Ont.) provided input on the accuracy of the sidereal time equation. The o b s e r v e r ’s h a n d b o o k could not exist without the strong, voluntary support of its twenty-four contributors and the provision of pre-publication material from The Astronomical Almanac by both the Nautical Almanac Office of the U.S. Naval Observatory and Her Majesty’s Nautical Almanac Office of the Royal Greenwich Observatory. Additional support is provided by Rosemary Freeman, Executive- Secretary of The Royal Astronomical Society of Canada, and by the Department of Physics, Acadia University, Nova Scotia. In the latter instance, I especially wish to acknowledge the careful preparation of the lunar occultation tables, in both this and the previous two editions, by Julia Melzer.