The Equatorie

The Equatorie of the Planetis in Peterhouse MS 75.I describes an instrument for calculating the positions of the planets. On the evidence of its calendar references the text was probably composed in 1393. For an astronomical work of this date, it is remarkable for being written in English. When it was brought to public attention by Derek J. Price in 1951 it naturally invited comparison with Chaucer’s A Treatise on the Astrolabe. Accompanying the Equatorie, and in the same hand, is a set of tables, one of which contains the note ‘Radix Chaucer’. The consequent possibility that the Equatorie was Chaucer’s own composition is an issue that has occupied the attention of many scholars; however, the astronomical content of the manuscript is also of considerable value in its own right. The WebGL version of the Equatorie works in it's own right and follows the instructions laid out in the manuscript. It is accurate to within a degree for the positions of the planets in the Solar system, and has been compared to both PyEmphem and the NASA Horizons project. [ Editors note ] Read more here: http://www.section9.co.uk/posts/2014-05-28-Equatorie.html