Free Astronomy Books

This is the updated list of astronomy books available for free download or online reading. These books and papers cover all the areas of astrophysics, cosmology, galactic and extragalactic astronomy, solar and stellar physics, celestial mechanics, planetary science, astrobiology, as well as some popular works. The books are made available free of charge to the reader by their authors or publishers. Here is a categorized directory of astronomy books. This page is updated daily.

1. Spherical Astronomy
   F. Brünnow | Van Nostrand, Published in 1865, 559 pages
2. An introductory treatise on the lunar theory
   Ernest W Brown | Cambridge University Press, Published in 1896, 312 pages
3. To See the Unseen: A History of Planetary Radar Astronomy
   Andrew J. Butrica | NASA History Division, Published in 1996, 301 pages
4. An Introduction to Celestial Mechanics
   Forest Ray Moulton | The MacMillan Company, Published in 1914, 437 pages
5. The Elements of Theoretical and Descriptive Astronomy
   Charles J. White | J. Wiley, Published in 1909, 322 pages
6. An Introduction to Astronomy
   Forest Ray Moulton | The MacMillan Company, Published in 1916, 577 pages
7. Galaxies and the Expanding Universe
   James Schombert | University of Oregon, Published in 2008
8. The Fundamentals of Stellar Astrophysics
   George W. Collins, II | W H Freeman & Co, Published in 2003, 494 pages
9. Particle Physics and Inflationary Cosmology
   Andrei Linde | arXiv, Published in 2005, 270 pages
10. Quantization in Astrophysics, Brownian Motion, and Supersymmetry
    F. Smarandache, V. Christianto | MathTiger, Published in 2007, 516 pages
11. Mysteries of the Sun
    Ginger Butcher | NASA, Published in 2011, 20 pages
12. Caldwell Catalogue
    | Wikipedia, Published in 2014
13. The Telescope
    Louis Bell | McGraw-Hill, Published in 1922, 294 pages
14. Massive Stars and their Supernovae
    F. Thielemann, R. Hirschi, M. Liebendorfer, R. Diehl | arXiv, Published in 2010, 81 pages
15. Neutrinos and the Stars
    Georg Raffelt | arXiv, Published in 2012, 83 pages
16. Cluster Lenses
    Jean-Paul Kneib, Priyamvada Natarajan | arXiv, Published in 2012, 120 pages
17. Amateur Telescope Making
    | Springfield Telescope Makers Inc, Published in 2018, 428 pages
18. Astrochemistry: The Issue of Molecular Complexity in Astrophysical Environments
    M. De Becker | arXiv, Published in 2013, 62 pages
19. A Briefer History of Time: From the Big Bang to the Big Mac
    Eric Schulman | St. Martin's Press, Published in 2004, 207 pages
20. Space Nomads
    Leota Jean LaPaz, Lincoln LaPaz | Holiday House, Published in 1961, 199 pages
21. Radiative Processes in High Energy Astrophysics
    Gabriele Ghisellini | arXiv, Published in 2012, 157 pages
22. History of Astronomy
    George Forbes | , Published in 1909
23. Primordial Magnetogenesis
    Alejandra Kandus, Kerstin E. Kunze, Christos G. Tsagas | arXiv, Published in 2011, 107 pages
24. An Introduction into the Theory of Cosmological Structure Formation
    Christian Knobel | arXiv, Published in 2012, 102 pages
25. On the Origin (and Evolution) of Baryonic Galaxy Halos
    Duncan A. Forbes, Ericson D. Lopez | MDPI AG, Published in 2018, 232 pages
26. A practical guide to Basic Statistical Techniques for Data Analysis in Cosmology
    Licia Verde | arXiv, Published in 2008, 52 pages
27. The History of Astrometry
    Michael Perryman | arXiv, Published in 2012, 52 pages
28. A New Astronomy
    David Peck Todd | American Book Company, Published in 1906, 437 pages
29. The Birth And Death Of The Sun
    George Gamow | Dover Publications, Published in 1940, 256 pages
30. From Cosmic Birth to Living Earths: The Future of UVOIR Space Astronomy
    Julianne Dalcanton, et al. | arXiv, Published in 2015, 176 pages
31. Introduction to Supersymmetry: Astrophysical and Phenomenological Constraints
    Keith A. Olive | arXiv, Published in 1999, 67 pages
32. High Performance Computing and Numerical Modelling
    Volker Springel | arXiv, Published in 2014, 108 pages
33. Lunar Orbiter Photographic Atlas of the Moon
    D.E. Hughes, J.K. Bowker | Lunar and Planetary Institute, Published in 1971
34. Celestial Mechanics: Notes and Work
    J.D. Mireles James | Rutgers University, Published in 2007, 128 pages
35. Habitable Planets for Man
    Stephen H. Dole | RAND Corporation, Published in 1964, 176 pages
36. Gravitational Wave Detection by Interferometry
    Matthew Pitkin, Stuart Reid, Sheila Rowan, Jim Hough | arXiv, Published in 2011, 80 pages
37. Elementary Mathematical Astronomy
    C. Barlow, G. Bryan | University Correspondence College Press, Published in 1893, 442 pages
38. Advanced Topics in Cosmology: A Pedagogical Introduction
    T. Padmanabhan | arXiv, Published in 2006, 40 pages
39. Black Holes
    P.K. Townsend | arXiv, Published in 1997, 145 pages
40. Exoplanet Observing for Amateurs
    Bruce L. Gary | Reductionist Publications, Published in 2007, 170 pages
41. The Beginning and the End: The Meaning of Life in a Cosmological Perspective
    Clement Vidal | arXiv, Published in 2013, 356 pages
42. An Introduction to Quantum Cosmology
    D.L. Wiltshire | arXiv, Published in 2003, 60 pages
43. Astronomy with an Opera-glass
    Garrett Putman Serviss | D. Appleton & co., Published in 1890, 154 pages
44. Celestial Navigation, Elementary Astronomy, Piloting
    Arturo Chiesa, Raffaele Chiesa | Sky and Sea Software, Published in 2010
45. Basaltic Volcanism on the Terrestrial Planets
    | Pergamon Press, Published in 1981, 1286 pages
46. Star-Gazer's Hand-Book
    Henry William Elson | Sturgis & Walton, Published in 1910, 72 pages
47. Hubble Space Telescope: Discoveries
    | NASA, Published in 2012, 128 pages
48. Ultrahigh Energy Cosmic Rays: Facts, Myths, and Legends
    Luis Alfredo Anchordoqui | arXiv, Published in 2011, 92 pages
49. Observational Probes of Cosmic Acceleration
    David H. Weinberg, et al. | arXiv, Published in 2012, 253 pages
50. Planetary Photometry
    Max Fairbairn | , Published in 2005
51. String Cosmology
    James M. Cline | arXiv, Published in 2007, 47 pages
52. Stellar Superfluids
    Dany Page, et al. | arXiv, Published in 2013, 88 pages
53. Cosmic Journey: A History of Scientific Cosmology
    N. S. Hetherington, W. P. McCray | American Institute of Physics, Published in 2009
54. An Introduction to Cosmic Rays and Gamma-Ray Bursts
    A. De Rujula | arXiv, Published in 2007, 37 pages
55. Atlas of Peculiar Galaxies
    Halton C. Arp | California Institute of Technology, Published in 1966, 190 pages
56. The Fine-Tuning of the Universe for Intelligent Life
    Luke A. Barnes | arXiv, Published in 2011, 76 pages
57. Advances in Modern Cosmology
    Adnan Ghribi | InTech, Published in 2011, 198 pages
58. A Simple Guide to Backyard Astronomy
    Carol Beigel | , Published in 2008, 61 pages
59. A Text-book of Astronomy
    George C. Comstock | D. Appleton and company, Published in 1901, 391 pages
60. Pioneers of Science
    Oliver Lodge | Macmillan and co, Published in 1905, 421 pages
61. An Introduction to Galactic Chemical Evolution
    Nikos Prantzos | arXiv, Published in 2007, 46 pages
62. Introduction to Physical Astronomy
    Kenneth R. Koehler | University of Cincinnati, Published in 2010
63. Trans-Neptunian Objects: An Overview
    | Wikipedia, Published in 2014
64. Cosmology
    V. A. Rubakov | arXiv.org, Published in 2018, 56 pages
65. Gamma-Ray Bursts: Progress, Problems and Prospects
    Bing Zhang, Peter Meszaros | arXiv, Published in 2008, 87 pages
66. Cosmology Primer
    Sean Carroll | preposterousuniverse.com, Published in 2012, 120 pages
67. The Birth and Death of Stars
    James Schombert | University of Oregon, Published in 2008
68. Dynamics of the Universe in Problems
    Yu. L. Bolotin, et al. | UniverseInProblems.com, Published in 2013, 113 pages
69. Short History of Astronomy
    Arthur Berry | John Murray, Published in 1898, 439 pages
70. Traces of Catastrophe
    Bevan M French | Lunar and Planetary Institute, Published in 1998, 120 pages
71. Plasma Physics of Extreme Astrophysical Environments
    Dmitri A. Uzdensky, Shane Rightley | arXiv, Published in 2014, 56 pages
72. Gravitational Wave Experiments and Early Universe Cosmology
    Michele Maggiore | arXiv, Published in 2000, 100 pages
73. TASI Lectures: Introduction to Cosmology
    Mark Trodden, Sean M. Carroll | arXiv, Published in 2004, 82 pages
74. Encyclopedia of Astrophysics
    Søren Bertil F. Dorch | Scholarpedia, Published in 2009
75. Telescopic Work for Starlight Evenings
    William F. Denning | Taylor and Francis, Published in 1891, 372 pages
76. Images of the Solar Upper Atmosphere From SUMER on SOHO
    Uri Feldman, at al. | ESA Publications Division, Published in 2003, 209 pages
77. Radiative Gas Dynamics
    David Weinberg | Ohio State University, Published in 2007
78. Supernova Cosmology: Legacy and Future
    Ariel Goobar, Bruno Leibundgut | arXiv, Published in 2011, 62 pages
79. A Review of the Universe: Structures, Evolutions, Observations, and Theories
    | universe-review.ca, Published in 2009
80. Astronomy Notes
    Nick Strobel | astronomynotes.com, Published in 2010
81. Voyager 1 Encounters Saturn
    | NASA, Published in 1980, 51 pages
82. Mars Science Laboratory
    | Wikipedia, Published in 2014
83. Resources of Near-Earth Space
    J. S. Lewis, M. S. Matthews | University of Arizona Press, Published in 1993, 977 pages
84. Black-Hole Phenomenology
    Neven Bilic | arXiv, Published in 2006, 58 pages
85. Recent Developments in Gravitational Collapse and Spacetime Singularities
    Pankaj S. Joshi, Daniele Malafarina | arXiv, Published in 2012, 89 pages
86. Vision and Voyages for Planetary Science in the Decade 2013-2022
    | National Academy of Sciences, Published in 2011, 410 pages
87. Dark Energy: Observational Evidence and Theoretical Models
    B. Novosyadlyj, V. Pelykh, Yu. Shtanov, A. Zhuk | Akademperiodyka, Published in 2013, 380 pages
88. Large Scale Structure of the Universe
    Alison L. Coil | arXiv, Published in 2012, 43 pages
89. Astronomy for Amateurs
    Camille Flammarion | D. Appleton and Company, Published in 1910
90. Galaxy systems in the optical and infrared
    A. Biviano | arXiv, Published in 2008, 60 pages
91. Gamma-Ray Bursts
    | Wikipedia, Published in 2014
92. Recreations in Astronomy
    Henry White Warren | Project Gutenberg,
93. Primer Of Celestial Navigation
    John Favill | Cornell Maritime Press, Published in 1944, 300 pages
94. Applied Cosmography: A Pedagogical Review
    Yu. L. Bolotin, et al. | arXiv.org, Published in 2018, 66 pages
95. The Foundations of Celestial Mechanics
    George W. Collins, II | Pachart Pub House, Published in 2004, 145 pages
96. From Chaos to Consciousness: A Brief History of the Universe
    Mike Corwin | Bookboon, Published in 2015, 166 pages
97. The world according to the Hubble Space Telescope
    Mario Livio | arXiv.org, Published in 2008, 112 pages
98. The Complete Idiot's Guide to The Sun
    Jay M. Pasachoff | Alpha, Published in 2003, 350 pages
99. Observations of the High Redshift Universe
    Richard S. Ellis | arXiv, Published in 2007, 115 pages
100. The First Stars
     Simon C. O. Glover | arXiv, Published in 2012, 72 pages
101. Multi-messenger Astronomy and Dark Matter
     Las Bergstrom | arXiv, Published in 2012, 105 pages
102. Voyager Encounters Jupiter
     | National Aeronautics and Space Administration, Published in 1979, 48 pages
103. Pioneer Saturn Encounter
     | NASA, Published in 1979, 45 pages
104. Solar Neutrinos
     V. Antonelli, L. Miramonti, C. Pena-Garay, A. Serenelli | arXiv, Published in 2012, 51 pages
105. Mechanism of the Heavens
     Mary Somerville | J. Murray, Published in 1831, 710 pages
106. The Astronomy of the Bible
     E. Walter Maunder | Richard Clay & Sons, Published in 1908
107. The Star Splitters: The High Energy Astronomy Observatories
     Wallace H. Tucker | NASA History Office, Published in 1984, 182 pages
108. Textbook on Practical Astronomy
     George Leonard Hosmer | Wiley, Published in 1910, 252 pages
109. Everything You Always Wanted To Know About The Cosmological Constant Problem
     Jerome Martin | arXiv, Published in 2012, 89 pages
110. Superstring Cosmology
     James E. Lidsey, David Wands, E. J. Copeland | arXiv, Published in 2000, 161 pages
111. Practical Astronomy for Engineers
     Frederick Hanley Seares | Stephens, Published in 1909, 160 pages
112. Introduction to Non-Baryonic Dark Matter
     Paolo Gondolo | arXiv, Published in 2004, 51 pages
113. Cosmology: The Study of the Universe
     | NASA, Published in 2009, 38 pages
114. High Energy Astrophysics
     Jonathan Katz | The Benjamin/Cummings Publishing, Published in 1986, 338 pages
115. Curiosities of the Sky
     Garrett Putman Serviss | Harper & Brothers, Published in 1909, 300 pages
116. Protoplanetary Disks and Their Evolution
     Jonathan P. Williams, Lucas A. Cieza | arXiv, Published in 2011, 65 pages
117. Astrodynamics: A Compendium of Orbitology
     | Wikipedia, Published in 2013, 334 pages
118. Celestial Mechanics
     J. B. Tatum | , Published in 2008
119. Ekpyrotic and Cyclic Cosmology
     Jean-Luc Lehners | arXiv, Published in 2009, 79 pages
120. Protostars and Planets
     | Rice University, Published in 2015, 422 pages
121. Man's Place in the Universe
     Alfred R. Wallace | Chapman and Hall, Published in 1904, 330 pages
122. The Formation and Evolution of the Solar System
     James Schombert | University of Oregon, Published in 2007
123. Through the Telescope
     James Baikie | Adam and Charles Black, Published in 1906, 303 pages
124. The Story of Eclipses
     George F. Chambers | S. S. McClure Co., Published in 1909, 208 pages
125. Observatories in Space
     Catherine Turon | arXiv, Published in 2011, 50 pages
126. Cosmology
     James Schombert | University of Oregon, Published in 2008
127. Introduction to the Theory of Black Holes
     Gerard 't Hooft | Utrecht University, Published in 2009, 49 pages
128. Cosmology for Particle Physicists
     U. A. Yajnik | arXiv, Published in 2008, 63 pages
129. Special Functions: Fractional Calculus and the Pathway for Entropy
     Hans J. Haubold (ed.) | MDPI AG, Published in 2018, 306 pages
130. Mathematical Theories of Planetary Motions
     Otto Dziobek | The Register Pub. Co., Published in 1892, 314 pages
131. Lecture notes on the formation and early evolution of planetary systems
     Philip J. Armitage | arXiv, Published in 2010, 63 pages
132. Understanding Galaxy Formation and Evolution
     V. Avila-Reese | arXiv, Published in 2006, 50 pages
133. Mag 7 Star Atlas Project
     Andrew L. Johnson | , Published in 2007, 21 pages
134. From Disks to Planets
     Andrew N. Youdin, Scott J. Kenyon | arXiv, Published in 2012, 70 pages
135. Introduction to Cosmology
     A. D. Dolgov | arXiv, Published in 2009, 58 pages
136. Cosmology and Astrophysics
     Juan Garcia-Bellido | arXiv.org, Published in 2005, 76 pages
137. Advances in Global and Local Helioseismology: an Introductory Review
     Alexander G. Kosovichev | arXiv, Published in 2011, 86 pages
138. Sky Surveys
     S. G. Djorgovski, A.A. Mahabal, A.J. Drake, M.J. Graham, C. Donalek | arXiv, Published in 2012, 62 pages
139. Solar System
     | Wikipedia, Published in 2012, 646 pages
140. An Introduction to the Theory of Rotating Relativistic Stars
     Eric Gourgoulhon | arXiv, Published in 2010, 88 pages
141. Guidebook to the Geology of Barringer Meteorite Crater, Arizona
     David A. Kring | Lunar and Planetary Institute, Published in 2007, 154 pages
142. Astronomical Discovery
     Herbert Hall Turner | E. Arnold, Published in 1904, 225 pages
143. Cosmological Evolution of Galaxies
     Isaac Shlosman | arXiv, Published in 2012, 88 pages
144. Evolution of the Solar System
     Hannes Alfven, Gustaf Arrhenius | NASA, Published in 1976
145. General Astronomy
     | Wikibooks, Published in 2009
146. Lunar Stratigraphy and Sedimentology
     John Lindsay | Elsevier, Published in 1976, 311 pages
147. The Planet Mars: A History of Observation and Discovery
     William Sheehan | University of Arizona Press, Published in 1996, 270 pages
148. Dwarf-Galaxy Cosmology
     Regina Schulte-Ladbeck, at al. | Hindawi Publishing, Published in 2010, 238 pages
149. Planetary Rings
     Matthew S. Tiscareno | arXiv, Published in 2011, 82 pages
150. The Cosmological Constant
     Sean M. Carroll | arXiv, Published in 2000, 50 pages
151. Cosmic Rays in Galactic and Extragalactic Magnetic Fields
     F. Aharonian, A. Bykov, E. Parizot, V. Ptuskin, A. Watson | arXiv, Published in 2011, 43 pages
152. Practical Astronomy
     George L. Hosmer | John Wiley and Sons Inc., Published in 1925, 314 pages
153. Inflation
     Marieke Postma | NIKHEF, Published in 2009, 53 pages
154. Astronomical Image and Data Analysis
     J.-L. Starck, F. Murtagh | Springer, Published in 2006, 335 pages
155. Searching for Life Across Space and Time
     | The National Academies Press, Published in 2017, 133 pages
156. Handbook of Space Astronomy and Astrophysics
     Martin V. Zombeck | Cambridge University Press, Published in 2006, 780 pages
157. Astronomy of To-day
     Cecil Goodrich Julius Dolmage | Seeley and co., Published in 1910
158. A Photographic Atlas of Rock Breakdown Features in Geomorphic Environments
     Mary Bourke, Heather Viles | Planetary Science Institute, Published in 2007, 88 pages
159. Introductory Lectures on Quantum Cosmology
     J. J. Halliwell | arXiv, Published in 1990, 107 pages
160. An Overview of the Solar System
     | Wikipedia, Published in 2013
161. A Handbook of Descriptive and Practical Astronomy
     George F. Chambers | Oxford At The Clarendon Press, Published in 1889, 756 pages
162. Chemistry in Protoplanetary Disks
     Thomas Henning, Dmitry Semenov | arXiv, Published in 2013, 84 pages
163. Techniques of Radio Astronomy
     T. L. Wilson | arXiv, Published in 2011, 47 pages
164. The Geology of the Terrestrial Planets
     Michael H. Carr | NASA, Published in 1984, 322 pages
165. Introduction to relativistic astrophysics and cosmology through Maple
     V. L. Kalashnikov | arXiv, Published in 2001, 124 pages
166. The Astrobiology Primer: An Outline of General Knowledge
     Lucas J. Mix, at al. | arXiv, Published in 2006, 79 pages
167. Observing the Sky from 40N
     Roberto Mura | Wikibooks, Published in 2010, 86 pages
168. Magnetic Fields, Strings and Cosmology
     Massimo Giovannini | arXiv, Published in 2006, 76 pages
169. The Practical Astronomer
     Thomas Dick | Seeley, Burnside, and Seeley, Published in 1845, 588 pages
170. General Astronomy
     Harold Spencer Jones | Edward Arnold and Company, Published in 1924, 392 pages
171. Consolidated Lunar Atlas
     Gerald P. Kuiper, et al. | Lunar and Planetary Institute, Published in 1960
172. First Light
     Abraham Loeb | arXiv, Published in 2006, 157 pages
173. Cosmic Microwave Background Anisotropies up to Second Order
     Nicola Bartolo, Sabino Matarrese, Antonio Riotto | arXiv, Published in 2007, 53 pages
174. Origin of the Moon
     W. K. Hartmann, R. J. Phillips, G. J. Taylor | Lunar and Planetary Institute, Published in 1986, 781 pages
175. Stellar Atmospheres
     J. B. Tatum | , Published in 2006
176. Notes on Stellar Astrophysics
     James N. Pierce | Minnesota State University, Published in 2013, 299 pages
177. Planetary Science: A Lunar Perspective
     Stuart Ross Taylor | Lunar and Planetary Institute, Published in 1982
178. Voyager 1 and 2: Atlas of Six Saturnian Satellites
     Raymond M. Batson | NASA, Published in 1984, 175 pages
179. Cosmic Structure, Averaging and Dark Energy
     David L. Wiltshire | arXiv, Published in 2013, 55 pages
180. Great Astronomers
     Robert S. Ball | Isbister, Published in 1895, 392 pages
181. The Cosmic Web: Geometric Analysis
     Rien van de Weygaert, Willem Schaap | arXiv, Published in 2007, 129 pages
182. Lectures on Inflation and Cosmological Perturbations
     David Langlois | arXiv, Published in 2010, 56 pages
183. Inflationary Cosmology and Structure Formation
     J. A. Peacock | arXiv, Published in 1996, 77 pages
184. Dense Matter in Compact Stars
     Andreas Schmitt | arXiv, Published in 2010, 146 pages
185. An Introduction to Celestial Mechanics
     Richard Fitzpatrick | The University of Texas at Austin, Published in 2011, 216 pages
186. Moon Trip: A Personal Account of the Apollo Program and its Science
     Elbert A. King | Lunar and Planetary Institute, Published in 1989, 162 pages
187. Lectures on Astronomy, Astrophysics, and Cosmology
     Luis A. Anchordoqui | arXiv, Published in 2007, 41 pages
188. Guide to Lunar Orbiter Photographs
     Thomas P. Hansen | NASA, Published in 1970, 127 pages
189. Mercury
     F. Vilas, C. Chapman, M. Matthews | University of Arizona Press, Published in 1989, 794 pages
190. Why CMB physics?
     Massimo Giovannini | arXiv, Published in 2007, 179 pages
191. Inflation and String Theory
     Daniel Baumann, Liam McAllister | arXiv, Published in 2014, 349 pages
192. Elements of Astrophysics
     Nick Kaiser | University of Hawaii, Published in 2002, 435 pages
193. To a Rocky Moon: A Geologist's History of Lunar Exploration
     Don E. Wilhelms | University of Arizona Press, Published in 1993, 524 pages
194. Planetary Theory
     Ernest Brown, Clarence Shook | Cambridge University Press, Published in 1933, 323 pages
195. Lopsided Spiral Galaxies
     Chanda J. Jog, Francoise Combes | arXiv, Published in 2008, 75 pages
196. The Hubble Constant
     Neal Jackson | arXiv, Published in 2014, 48 pages
197. Frequently Asked Questions about Calendars
     Claus Tøndering | , Published in 2008, 65 pages
198. Are We Alone?
     Gregg Easterbrook | The Atlantic Monthly, Published in 1988
199. A Primer for Black Hole Quantum Physics
     R. Brout, S. Massar, R. Parentani, P. Spindel | arXiv, Published in 2007, 178 pages
200. Introduction to Dark Matter Experiments
     R. W. Schnee | arXiv.org, Published in 2011, 64 pages
201. Introduction to Cosmology
     David H Lyth | arXiv, Published in 1993, 53 pages
202. Lectures on Black Holes, Topological Strings and Quantum Attractors
     Boris Pioline | arXiv, Published in 2007, 103 pages
203. Particle Physics Aspects of Modern Cosmology
     Robert H. Brandenberger | arXiv, Published in 1997, 70 pages
204. When Biospheres Collide: A History of NASA's Planetary Protection Programs
     Michael Meltzer | NASA, Published in 2011, 542 pages
205. Introduction to Millimeter/Sub-Millimeter Astronomy
     T. L. Wilson | arXiv, Published in 2009, 106 pages
206. Supernovae
     | Wikipedia, Published in 2014
207. The Shape of the Universe
     Gerd Pommerenke | viXra, Published in 2013, 321 pages
208. Mathematical Problems Of Radiative Equilibrium
     Eberhard Hopf | Cambridge University Press, Published in 1934, 123 pages
209. Hubble 25: A Quarter-Century of Discovery with the Hubble Space Telescope
     Dylan Steele (ed.) | NASA, Published in 2015, 78 pages
210. The Beginning and Evolution of the Universe
     Bharat Ratra, Michael S. Vogeley | arXiv, Published in 2008, 69 pages
211. Chondrules and their Origins
     Elbert A. King | The Lunar and Planetary Institute, Published in 1983, 377 pages
212. Hours With A Three-Inch Telescope
     William Noble | Longmans, Green & Co., Published in 1887, 159 pages
213. Observing the Sky from 30S
     Roberto Mura | Wikibooks, Published in 2010, 86 pages
214. An Exposition on Inflationary Cosmology
     Scott Watson | arXiv, Published in 2000, 93 pages
215. Elementary Astronomy
     James N. Pierce | , Published in 2013, 134 pages
216. An Expanded View of the Universe
     | European Southern Observatory, Published in 2011, 54 pages
217. Atomic and Molecular Processes in Astronomy and Planetary Science
     Geoffrey A. Blake | California Institute of Technology, Published in 2004
218. The Virial Theorem in Stellar Astrophysics
     George W. Collins, II | Pachart Pub. House, Published in 1978, 135 pages
219. Primordial Nucleosynthesis: from precision cosmology to fundamental physics
     F. Iocco, G. Mangano, G. Miele, O. Pisanti, P.D. Serpico | arXiv, Published in 2009, 148 pages
220. The Universe in a Helium Droplet
     Grigory E. Volovik | Oxford University Press, Published in 2003, 532 pages
221. Cosmology: Mankind's Grand Investigation
     Greg Bothun | Harcourt Brace College Publishers, Published in 1999, 129 pages
222. Introduction to Early Universe Cosmology
     Robert H. Brandenberger | arXiv, Published in 2011, 70 pages
223. The Solar Magnetic Field
     Sami Solanki, Bernd Inhester, Manfred Schussler | arXiv, Published in 2010, 83 pages
224. Cosmic Rays and the Search for a Lorentz Invariance Violation
     Wolfgang Bietenholz | arXiv, Published in 2008, 81 pages
225. Archaeology, Anthropology, and Interstellar Communication
     Douglas A. Vakoch | NASA, Published in 2014, 330 pages
226. Photographs of Nebulae and Clusters
     James Edward Keeler | University of California Publications, Published in 1908
227. The Galactic Habitable Zone I. Galactic Chemical Evolution
     G. Gonzalez, D. Brownlee, P. Ward | arXiv, Published in 2001, 57 pages
228. Gravitational Waves: Sources, Detectors and Searches
     Keith Riles | arXiv, Published in 2012, 79 pages
229. Big Bang Nucleosynthesis and Physics Beyond the Standard Model
     Subir Sarkar | arXiv, Published in 1996, 156 pages
230. Views of the Solar System
     Calvin J. Hamilton | , Published in 2008
231. Astronomy
     Andrew Fraknoi, David Morrison, Sidney C. Wolff | Unglue.it, Published in 2016, 1200 pages
232. Supernova Remnants: The X-ray Perspective
     Jacco Vink | arXiv, Published in 2011, 78 pages
233. Oulu Space Physics Textbook
     Reijo Rasinkangas | University of Oulu, Published in 2008
234. A Practical Introduction to Numerical Hydrodynamics
     Garrelt Mellema | Leiden University, Published in 2003
235. A Guide To The Constellations
     Samuel G. Barton | McGraw-Hill, Published in 1928, 96 pages
236. Modified Gravity and Cosmology
     T. Clifton, P.G. Ferreira, A. Padilla, C. Skordis | arXiv, Published in 2012, 312 pages
237. Cosmos and Culture: Cultural Evolution in a Cosmic Context
     Steven J. Dick, Mark L. Lupisella | NASA, Published in 2010, 612 pages
238. Practical Astronomy
     P. S. Michie, F. S. Harlow | John Wiley & Sons, Published in 1893, 246 pages