Search results
Results from the WOW.Com Content Network
The horopter as a special set of points of single vision was first mentioned in the eleventh century by Ibn al-Haytham, known to the west as "Alhazen". [3] He built on the binocular vision work of Ptolemy [4] and discovered that objects lying on a horizontal line passing through the fixation point resulted in single images, while objects a reasonable distance from this line resulted in double ...
[6] [7] [8] Quizlet's blog, written mostly by Andrew in the earlier days of the company, claims it had reached 50,000 registered users in 252 days online. [9] In the following two years, Quizlet reached its 1,000,000th registered user. [10] Until 2011, Quizlet shared staff and financial resources with the Collectors Weekly website. [11]
The works of Ptolemy (astronomy) and Galen (medicine) were found not always to match everyday observations. Work by Vesalius on human cadavers found problems with the Galenic view of anatomy. [187] The discovery of Cristallo contributed to the advancement of science in the period as well with its appearance out of Venice around 1450.
Opening chapter of the first printed edition of Ptolemy's Tetrabiblos, transcribed into Greek and Latin by Joachim Camerarius (Nuremberg, 1535).. The commonly known Greek and Latin titles (Tetrabiblos and Quadripartitum respectively), meaning 'four books', are traditional nicknames [24] for a work which in some Greek manuscripts is entitled Μαθηματικὴ τετράβιβλος ...
Three important textbooks, written shortly before Ptolemy's time, were written by Cleomedes, Geminus, and Theon of Smyrna. Books by Roman authors like Pliny the Elder and Vitruvius contain some information on Greek astronomy. The most important primary source is the Almagest, since Ptolemy refers to the work of many of his predecessors. [3]
The Planisphaerium is a work by Ptolemy. The title can be translated as "celestial plane" or "star chart". In this work Ptolemy explored the mathematics of mapping figures inscribed in the celestial sphere onto a plane by what is now known as stereographic projection. This method of projection preserves the properties of circles.
Ptolemy did not predict the relative sizes of the planetary deferents in the Almagest. All of his calculations were done with respect to a normalized deferent, considering a single case at a time. This is not to say that he believed the planets were all equidistant, but he had no basis on which to measure distances, except for the Moon.
In 850, al-Farghani wrote his own summary of the work, titled Kitab fi Jawani Ilm al-Nujum ("A compendium of the science of stars"), a summary of Ptolemic cosmography. The primary purpose of the work was to help explicate Ptolemy's, but it also included some corrections based on the findings of earlier Arab astronomers.