Exploring The Planets-Discovery - The five known in antiquity, three more since the telescope, and Ceres. www.nasm.si.edu/ceps/etp/discovery/etpdiscovery.html
Neptune and Pluto - Mathematical discovery of planets www-groups.dcs.st-and.ac.uk/~history/HistTopics/Neptune_and_Pluto.html
Neptune's Discovery - Article in Astronomy Magazine. www.astronomy.com/Content/Dynamic/Articles/000/000/000/119ipise.asp
Notes on Sunspot Observations - John Winthrop's 1739 notes, from the collected papers of Fredrick Kilgour. www.oclc.org/pdemo/kg/p012.htm
Orbits and Gravitation - The development of the mathematics of planetary motion. www-groups.dcs.st-and.ac.uk/~history/HistTopics/Orbits.html
Solar Astronomy - A timeline. www.gsu.edu/other/timeline/solar.html