The main object of the following chapters is to give a brief and simple description of the most important and interesting facts concerning the heavenly bodies, and to suggest to the general reader how much of the ground thus covered lies open to his personal survey on very easy conditions. Many people who are more or less interested in astronomy are deterred from making practical acquaintance with the wonders of the heavens by the idea that these are only disclosed to the possessors of large and costly instruments. In reality there is probably no science which offers to those whose opportunities and means of observation are restricted greater stores of knowledge and pleasure than astronomy; and the possibility of that quickening of interest which can only be gained by practical study is, in these days, denied to very few indeed.

Accordingly, I have endeavoured, while recounting the great triumphs of astronomical discovery, to give some practical help to those who are inclined to the study of the heavens, but do not know how to begin. My excuse for venturing on such a task must be that, in the course of nearly twenty years of observation with telescopes of all sorts and sizes, I have made most of the mistakes against which others need to be warned.

The book has no pretensions to being a complete manual; it is merely descriptive of things seen and learned. Nor has it any claim to originality. On the contrary, one of its chief purposes has been to gather into short compass the results of the work of others. I have therefore to acknowledge my indebtedness to other writers, and notably to Miss Agnes Clerke, Professor Young, Professor Newcomb, the late Rev. T. W. Webb, and Mr. W. F. Denning. I have also found much help in the Monthly Notices and Memoirs of the Royal Astronomical Society, and the Journal and Memoirs of the British Astronomical Association.

The illustrations have been mainly chosen with the view of representing to the general reader some of the results of the best modern observers and instruments; but I have ventured to reproduce a few specimens of more commonplace work done with small telescopes. I desire to offer my cordial thanks to those who have so kindly granted me permission to reproduce illustrations from their published works, or have lent photographs or drawings for reproduction—to Miss Agnes Clerke for Plates XXV.-XXVIII. and XXX.-XXXII. inclusive; to Mrs. Maunder for Plate VIII.; to M. Loewy, Director of the Paris Observatory, for Plates XI.-XIV. and Plate XVII.; to Professor E. B. Frost, Director of the Yerkes Observatory, for Plates I., VII., XV., and XVI.; to M. Deslandres, of the Meudon Observatory, for Plate IX., and the gift of several of his own solar memoirs; to the Astronomer Royal for England, Sir W. Mahony Christie, for Plate V.; to Mr. H. MacEwen for the drawings of Venus, Plate X.; to the Rev. T. E. R. Phillips for those of Mars and Jupiter, Plates XX. and XXII.; to Professor Barnard for that of Saturn, Plate XXIV., reproduced by permission from the Monthly Notices of the Royal Astronomical Society; to Mr. W. E. Wilson for Plates XXIX. and XXXII.; to Mr. John Murray for Plates XVIII. and XIX.; to the proprietors of Knowledge for Plate VI.; to Mr. Denning and Messrs. Taylor and Francis for Plate III. and Figs. 6 and 20; to the British Astronomical Association for the chart of Mars, Plate XXI., reproduced from the Memoirs; and to Messrs. T. Cooke and Sons for Plate II. For those who wish to see for themselves some of the wonders and beauties of the starry heavens the two Appendices furnish a few specimens chosen from an innumerable company; while readers who have no desire to engage in practical work are invited to skip Chapters I. and II.