away, some idea of the profundity of space is made manifest.
The following symbols are used in the diagrams:
◯ The outlined circle to indicate the double stars,
+ The cross to indicate the position of the nebule.
░ The group of dots to show the location of the star clusters.
The following abbreviations appear in the text:
A., Angle; D., Distance; H., Herschel; Mg., Magnitude; M., Messier; Σ, Wm. Struve; ΟΣΣ, Poulkova Catalogue, Part II; P., Piazzi Smyth; ΟΣ, Otto Struve.
In the compilation of this book I desire to acknowledge my indebtedness to Mr. Garrett P. Serviss, the author of The Moon and Pleasures of the Telescope, These books have been a positive inspiration to me, and the student is urged to include them in his collateral reading.
Mr. Serviss, than whom no one has done more to popularize the charming study of the stars, has the wonderful gift of imparting knowledge through the medium of a style that is altogether fascinating, and I take great pleasure in adding my mite of tribute to one who has afforded me through his numerous writings so many hours of unalloyed pleasure.
In preparing the list of objects suitable for observation, I derived much valuable information also from the following books:
