Medieval Astronomy - History of Astronomy
Welcome to Study Guides!

Medieval Astronomy

circular gold object with markings on it
Astrolabe in Hebrew, probably from Spain (1300s AD)

October 2016 - In the early Middle Ages, most people in Europe were too poor to have much time for astronomy. But some people were still interested in the stars: astrologers, who tried to predict the future, monks who wanted to figure out the right day to celebrate Easter, or the right times for prayers, and the few scholars who were carrying on Ptolemy's work relating geometry to astronomy.

man wearing glasses
da Modena, man wearing glasses (ca. 1350 AD)

Around 1100 AD, scholars in Islamic Spain translated ibn al-Haytham's great book, Optics, into Latin. Like Shen Gua in China, Roger Bacon, a Franciscan monk in England, read al-Haytham's work in the 1200s AD and learned about glass lenses, refraction, and how light and eyes worked. He learned how to build a camera obscura, and made curved glass magnifying lenses. Bacon's explanation of West Asian optics, in his Opus Majus (about 1267 AD), got optics added to the curriculum at the new universities of Europe. Twenty years later, Italian glassmakers made the first eyeglasses. These were convex lenses for far-sighted people.

Around 1350 AD, Nicole Oresme discussed various reasons for thinking that the earth went around the sun, though he said that he himself did not think that the earth moved. He also argued that astrology didn't work, because the movements of the planets were not as mathematically regular as astrologers thought.

By the 1450s, Italian glass-makers were also making concave lenses for near-sighted people. About the same time, Johann Muller of Germany showed that old astronomical tables were not very accurate - their prediction of an eclipse of the moon was off by a whole hour. Muller also built copies of Islamic astrolabes, and pointed out some problems with Ptolemy's theories of retrograde motion. When Gutenberg set up the first printing press with moveable metal type in 1454, Muller realized that this would make it easier to teach science accurately, without mistakes in copying, and he printed the world's first science books in 1471.

Around the same time, Europeans figured out how to use the Chinese magnetic compass to calculate your latitude (how far north or south you were) when you were out of sight of land, on a sailing ship. That made longer sea voyages safer, and soon Europeans started to explore the Atlantic Ocean.

Learn by doing: observe a lunar eclipse
Astronomy in the Renaissance

Bibliography and further reading about medieval astronomy:

Islamic astronomy
Medieval Science
Medieval Europe home

LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Study Guides
  • Publisher:
  • Date Published:
Did you find what you needed? Ask your teacher to link to this page so other people can use it too! Send it in and win a "Great Page!" award!
Sign up for more free articles and special offers in' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more? is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Study Guides, . Web. 28 April, 2017