History and Philosophy of Western Astronomy (Popularity: ): The History chapter of an introductory astronomy course. The Àryabhatíya of Àryabhata (Popularity: ): The oldest exact astronomic constant? The ratio of earth rotations to lunar orbits in Aryabhata's AD 498 writing. Astronomy in Japan (Popularity: ): Historical and modern Japanese astronomy, and its place in Japanese culture The Star of Bethlehem (Popularity: ): An investigation of the science and history which bear on the mysterious star said to have accompanied the advent of Christ. Rundetaarn (The Round Tower) (Popularity: ): Astronomy in Denmark: Brahe, Roemer, Hertzsprung. Hindu Cosmological Time Cycles (Popularity: ): An accurate calendar and the progenitor of the sexagesimal (base 60) "degree, minutes, seconds" measurement system. History of Astronomy Pages (Popularity: ): Frederik Kaiser (1808-1872) and the professionalisation of Dutch astronomy; The "Lost Letters" of J.C. Kapteyn (1851-1922); Many history of astronomy and history of science links with a Dutch flavour. Historical Astronomy Division (Popularity: ): American Astronomical Society division devoted to history, with a link to pages on the history of the society itself. A Brief SETI Chronology (Popularity: ): A timeline of the search for extraterrestrial intelligence, from Morrison and Coconni to SETI@home. A Science Odyssey - Physics and Astronomy (Popularity: ): PBS articles about 20th century astronomy and physics.