Image source: Creator Unknown 1790, Astronomy: a 40-foot telescope constructed by William Herschel, in use outdoors, Etching, Wellcome Library, accessed 27 November 2017, <https://wellcomecollection.org/works/djd4857p?query=a+40-foot+telescope+constructed+by+W.+Herschel+Wellcome+V0024766.jpg>, Creative Commons license: <https://creativecommons.org/licenses/by/4.0/>.
This web article from Khan Academy privides an overview of Ptolemy and his contributions to astronomy. There are also links on the left to information on other important figures in this history.
This webpage from Iowa State University's Polaris Project provides detailed information about the Ptolemy's model. There are also links to information about other astronomers.
Abdallah Muhammad Ibn Jabir Ibn Sinan al-Battani al-Harrani (Muhammad Al-Battani): 858 - 929 C.E.
This Wikipedia article provides a brief summary of Muhammad Al-Battani's contributions to astronomy. (nb: Wikipedia can be a helpful starting place for research.)
This webpage from the University of St Andrews' School of Mathematics and Statistics provides information on Khayyam's work as a poet and a mathematician.
This webpage from space.com provides a more detailed biography of Copernicus. It also has a video that looks at the discoveries by both Copernicus and Kepler.
This webpage from Prof Eric G Blackman (Department of Physics and Astronomy, University of Rochester) provides a focused overview of Tycho Brahe's contributions to astronomy.
