The Moon: A Full Description and Map of Its Principal Physical Features is a comprehensive and meticulously detailed exploration of Earth's only natural satellite, authored by Thomas Gwyn Elger. First published in the late 19th century, this classic work stands as a foundational text in lunar observation and selenography. Elger, an accomplished astronomer and lunar cartographer, presents a thorough account of the Moon's surface, offering readers both scientific insight and practical guidance for amateur and professional astronomers alike. The book opens with an accessible introduction to the history of lunar observation, tracing the evolution of telescopic studies and the contributions of notable astronomers. Elger then delves into the physical characteristics of the Moon, discussing its phases, libration, and the effects of light and shadow on its appearance. He provides a clear explanation of the methods and instruments best suited for lunar observation, emphasizing the importance of patience, careful recording, and the use of detailed maps. Central to the book is Elger's exhaustive description of the Moon's principal physical features. Each chapter is dedicated to a specific region or type of formation, such as craters, mountain ranges, valleys, and maria. Elger meticulously catalogs hundreds of features, describing their dimensions, shapes, and relative positions. He supplements these descriptions with his own detailed map, which was among the most accurate and comprehensive lunar maps of its time. The map and accompanying illustrations serve as invaluable tools for identifying and studying the Moon's surface. Throughout the text, Elger combines scientific rigor with a passion for discovery, encouraging readers to observe the Moon for themselves and contribute to the growing body of lunar knowledge. He addresses common observational challenges, offers tips for sketching and recording observations, and discusses the significance of ongoing lunar research. The Moon: A Full Description and Map of Its Principal Physical Features remains a significant historical resource, reflecting the state of lunar science in the late 19th century while providing timeless guidance for anyone fascinated by the Moon. Its blend of detailed descriptions, practical advice, and beautifully rendered maps makes it an essential reference for astronomers, historians of science, and lunar enthusiasts.
