It is a pleasure to present this work, which has been well received in German-speaking countries through four editions, to the English-speaking reader. We feel that this is a unique publication in that it contains valuable material that cannot easily-if at all-be found elsewhere. We are grateful to the authors for reading through the English version of the text, and for responding promptly (for the most part) to our queries. Several authors have supplied us, on their own initiative or at our suggestion, with revised and updated manuscripts and with supplementary English references. We have striven to achieve a translation of Handbuch fUr Sternfreunde which accurately presents the qualitative and quantitative scientific principles con­ tained within each chapter while maintaining the flavor of the original Ger­ man text. Where appropriate, we have inserted footnotes to clarify material which may have a different meaning and/or application in English-speaking countries from that in Germany. When the first English edition of this work, Astronomy: A Handbook (translated by the late A. Beer), appeared in 1975, it contained 21 chapters. This new edition is over twice the length and contains 28 authored chap­ ters in three volumes. At Springer's request, we have devised a new title, Compendium of Practical Astronomy, to more accurately reflect the broad spectrum of topics and the vast body of information contained within these pages.

Table of Contents:
of Volume 3.- 24 The Stars.- 24.1 The Positions of the Stars.- 24.2 Stellar Magnitudes and Colors.- 24.3 Trigonometric Determination of Distances to Nearby Stars.- 24.4 Absolute Magnitudes and Distance Moduli.- 24.5 Stellar Spectral Types.- 24.6 The Hertzsprung-Russell Diagram.- 24.7 Luminosity Classes.- 24.8 Two-Color Diagrams.- 24.9 Bolometric Magnitudes.- 24.10 Stellar Diameters.- 24.11 Stellar Temperatures.- 24.12 Stellar Masses.- 24.13 Energy Generation and Lifetime.- 24.14 The Chemical Composition of the Stars.- 24.15 The Evolution of Stars with Time.- 24.16 Subjects for Amateur Observations.- References.- 25 Variable Stars.- 25.1 Introduction.- 25.2 Nomenclature and Classification.- 25.3 Eclipsing Variables.- 25.4 Pulsating Variables.- 25.5 Rotating Variables.- 25.6 Eruptive Variables.- 25.7 Young Irregular Variables.- References.- 26 Binary Stars.- 26.1 General Overview.- 26.2 Features of Visual Double Stars.- 26.3 Micrometer and Visual Observations.- 26.4 Speckle and Photographic Observations.- 26.5 Orbital Elements and Ephemerides.- 26.6 Photometric Binaries.- References.- 27 The Milky Way Galaxy and the Objects Composing It.- 27.1 The Visual Appearance of the Milky Way.- 27.2 Interstellar Dust and Its Effects Upon Distance Determinations Within the Galaxy.- 27.3 The Galactic Objects: A Survey.- 27.4 Catalogues and Atlases of Galactic Nebulae.- 27.5 Open Clusters.- 27.6 The Globular Clusters.- 27.7 H II Regions.- 27.8 Reflection Nebulae.- 27.9 Galactic Cirrus or Hagen Clouds.- 27.10 Supernova Remnants.- 27.11 Planetary Nebulae.- 27.12 Molecular and Dark Clouds.- 27.13 Herbig-Haro Objects, Bipolar and Cometary Nebulae.- 27.14 The Structure of the Milky Way System.- 27.15 Hints for the Observer.- References.- 28 Extragalactic Objects.- 28.1 Introduction.- 28.2 Catalogues and Photomaterials.- 28.3 Classification of Galaxies.- 28.4 The Structure of Galaxies.- 28.5 Determination of Distances.- 28.6 Active Galaxies and Quasars.- 28.7 The Universe.- 28.8 Amateur Techniques and Projects.- References.- Appendix B: Astronomical Data.- B.0 Abbreviations and symbols used in astronomy, mathematics, and physics.- B.4 Normal refraction (for standard atmosphere at 1013 mb and 0°C).- B.5 Semi-diurnal arc (including normal refraction).- B.6 Astronomical constants.- B.7 Beginning and end times of twilight at 20-day intervals for different latitudes.- B.8 Julian day numbers.- B.9 Conversion of days into decimal fractions of the Julian Year.- B.11 Solar data.- B.12 Position angle P of the solar axis and heliographic latitude Bo of the apparent center of disk at 5-day intervals.- B.13 Coordinates of lunar formations in the Mucke-Rükl system.- B.14 Technique and exposure data for lunar and planetary photography.- B.15 Planetary data.- B.16 Temperature and atmospheric data for the major planets and the satellite Titan.- B.17 Planetary satellite data.- B.18 The IAU Mars map 1958.- B.19 Data on the bright minor planets.- B.20 Table of change of the central meridians of Mars and Jupiter.- B.21 Atmospheric currents on Jupiter.- B.22 Periodic comets with periods under 200 years, observed in more than one perihelion passage.- B.23 Brightness of the zodiacal light.- B.24 The 88 constellations.- B.25 The 170 brightestxStars (to visual magnitude +3.0).- B.26 The nearest stars (within 6 pc).- B.27 Absolute magnitudes of stars in the MK system.- B.29 Abbreviations of some chemical elements.- B.30 Wavelengths of selected spectral lines in visible light.- B.31 Radial velocities for selected stars.- B.32 Double stars.- B.33 The Messier list of nebulae andclusters (1784).- B.34 Open clusters.- B.35 Globular clusters.- B.36 Planetary nebulae.- B.37 Diffuse galactic nebulae.- B.38 The strongest emission lines in HII regions, with intensities given for the Orion Nebula.- B.39 Selected abbreviations of organisations and periodicals.- B.40 Abbreviations of reference catalogues.- Supplemental Reading List for Vol. 3.