Covering more than 3,000 astronomical terms, ranging from methods, instruments, and equations to famous astronomers, satellites, and stars, this book is an ideal reference for students, professionals, and astronomy enthusiasts. Each definition uses accessible vocabulary, thus eliminating the need for another dictionary to decipher the explanations. Presented in a glossary format with a paragraph defining each term, this comprehensive dictionary also includes 40 line drawings to illustrate equipment and complex ideas. Definitions of scientific terms from related fields such as physics, astronautics, and environmental sciences are also provided, highlighting modern developments and emphasizing historical significance.