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Canon of eclipses
Planet.SpaceSci. 1963.Vol. 11. pp. 995to 999. PergamonPressLtd. Printedin NorthernIreland
BOOK REVIEWS
TH. RITTER VON OPPOLZER,
Publications,
Canon of Eclipses (translated 1962. xx + 378 pp. 160 charts. 80s.
by Owen Gingerich).
Dover
PROFESWR
Theodor Ritter von Oppolzer was a great theoretical astronomer and a wonderful computer. His Lehrbuch zur Buhnbestimmung der Kometen und Planeten, published in 1882, is a classic example of his thorough approach, of his tireless energy, and of his mastership of computational technique; his treatment of finite differences, of numerical differentiation and integration, and of kindred matters, goes far beyond almost all other published treatments, even in this day of high-speed computers. Yet his name is so Ilrrnly associated with one publication that the word “Oppolzer” needs no qualification to signify his Cunon der Finsternisse, published in 1887. For those who do not know, and have never consulted, this masterpiece of the computational art of the astronomer let a few cold facts describe its content: (a) the elements and principal circumstances of all 8000 eclipses of the Sun from 1208 B.C. to A.D. 2161, enabling the local circumstances to be calculated simply for any place on the Earth; (b) similar data for all the 5200 eclipses of the Moon from 1207 B.C. to A.D. 2163; (c) 160 charts showing, for latitudes north of S. 30”, the tracks on the Earth’s surface of the paths of totality or annularity for all such solar eclipses; (d) a comprehensive description of the data given and of their use for the calculation of all local circumstances. The computation of similar data for a modern eclipse, such as is currently given in The Astronomical Ephemeris for the total solar eclipse of 1963 July 20, is quite a sizeable job for an electronic computer, starting from the known ephemerides of the Sun and Moon, Even when all allowances are made for the low precision, and for the approximations used, the amount of work required to produce the data in this volume is colossal; it was completed, to an extremely high standard of accuracy, with logarithms as the only computing aid. The data are, however, much more than a monument to computational genius; they have served, and will continue to serve, two most useful purposes: to give the occurrence and the circumstances of eclipses to a precision that is adequate for most planning requirements, and for many interesting investigations into periodicities; to provide invaluable reference standards for the comparison of ancient eclipses with the theories of the motion of the Sun and Moon. As pointed out in the informative and admirable Preface the data in this volume have already made an important contribution to the study of the motion of the Moon, or, as we now know (but Oppolzer did not) to the study of the variable rotation of the Earth. Modern electronic computers will probably be used for special investigations in the future, but these data are adequate for many fascinating studies. The volume under review is a photographic reproduction of the original edition, with the addition of the Preface, and of an English translation of the original German Introduction. It has beenbeautifullyproduced: the 378 pages of tables have been very slightly reduced in size, and the diagrams have been reduced by about 15 per cent but all are easily legible. The limiting dates covered by each chart have been inserted-a simple addition that will gratify every user. The translation of the Introduction is excellent, and meets a long-felt need; it has been set with great care and attention to detail. In fact this whole reprint has been prepared and produced to a standard befitting the original-and no praise could be higher. All astronomical libraries, and many non-astronomical libraries, must obtain this book-either to safeguard their much-consulted, probably rather dog-eared, original edition, or to acquire a unique combination of reference book and research tool. They can do so at a price which, in terms of cost per page (allowing for page size and content per page) is only one-quarter of that which some publishers now consider the scientific community can pay. D. H. SADLER
BOOK REVIEWS
TH. RITTER VON OPPOLZER,
Publications,
Canon of Eclipses (translated 1962. xx + 378 pp. 160 charts. 80s.
by Owen Gingerich).
Dover
PROFESWR
Theodor Ritter von Oppolzer was a great theoretical astronomer and a wonderful computer. His Lehrbuch zur Buhnbestimmung der Kometen und Planeten, published in 1882, is a classic example of his thorough approach, of his tireless energy, and of his mastership of computational technique; his treatment of finite differences, of numerical differentiation and integration, and of kindred matters, goes far beyond almost all other published treatments, even in this day of high-speed computers. Yet his name is so Ilrrnly associated with one publication that the word “Oppolzer” needs no qualification to signify his Cunon der Finsternisse, published in 1887. For those who do not know, and have never consulted, this masterpiece of the computational art of the astronomer let a few cold facts describe its content: (a) the elements and principal circumstances of all 8000 eclipses of the Sun from 1208 B.C. to A.D. 2161, enabling the local circumstances to be calculated simply for any place on the Earth; (b) similar data for all the 5200 eclipses of the Moon from 1207 B.C. to A.D. 2163; (c) 160 charts showing, for latitudes north of S. 30”, the tracks on the Earth’s surface of the paths of totality or annularity for all such solar eclipses; (d) a comprehensive description of the data given and of their use for the calculation of all local circumstances. The computation of similar data for a modern eclipse, such as is currently given in The Astronomical Ephemeris for the total solar eclipse of 1963 July 20, is quite a sizeable job for an electronic computer, starting from the known ephemerides of the Sun and Moon, Even when all allowances are made for the low precision, and for the approximations used, the amount of work required to produce the data in this volume is colossal; it was completed, to an extremely high standard of accuracy, with logarithms as the only computing aid. The data are, however, much more than a monument to computational genius; they have served, and will continue to serve, two most useful purposes: to give the occurrence and the circumstances of eclipses to a precision that is adequate for most planning requirements, and for many interesting investigations into periodicities; to provide invaluable reference standards for the comparison of ancient eclipses with the theories of the motion of the Sun and Moon. As pointed out in the informative and admirable Preface the data in this volume have already made an important contribution to the study of the motion of the Moon, or, as we now know (but Oppolzer did not) to the study of the variable rotation of the Earth. Modern electronic computers will probably be used for special investigations in the future, but these data are adequate for many fascinating studies. The volume under review is a photographic reproduction of the original edition, with the addition of the Preface, and of an English translation of the original German Introduction. It has beenbeautifullyproduced: the 378 pages of tables have been very slightly reduced in size, and the diagrams have been reduced by about 15 per cent but all are easily legible. The limiting dates covered by each chart have been inserted-a simple addition that will gratify every user. The translation of the Introduction is excellent, and meets a long-felt need; it has been set with great care and attention to detail. In fact this whole reprint has been prepared and produced to a standard befitting the original-and no praise could be higher. All astronomical libraries, and many non-astronomical libraries, must obtain this book-either to safeguard their much-consulted, probably rather dog-eared, original edition, or to acquire a unique combination of reference book and research tool. They can do so at a price which, in terms of cost per page (allowing for page size and content per page) is only one-quarter of that which some publishers now consider the scientific community can pay. D. H. SADLER