Renaissance+and+Reformation+Science

**//Six Phases of the Moon//** Galileo. //Six Phases of the Moon//. 1616. //ARTstor//. Web. 8 Dec. 2009. 
 * Multiple20Collection20Search|||type3D3126kw3DGalileo27s20Astronomy

During the Renaissance, Nicolaus Copernicus proposed a heliocentric model of the solar system. His work defended, expanded upon, and corrected Galileo Galilei and Johannes Kepler. Galileo innovated by using telescopes to enhance his observations. Further discoveries paralleled the improvements in the size and quality of the telescope. More extensive stars catalogues were produced by Lacaille. The astronomer Willian Herschel made a detailed catalog of nebulosity and clusters, and in 1781 discovered the planet Uranus, the first new planet found. The distance to a star was first announced in 1838 when the parallax of 61 Cygni was measured by Fridrich Bessel.

//**System of Ptolemy** System of Ptolemy//. N.d. //ARTstor//. Web. 8 Dec. 2009. .

The first part of the Geographia is a discussion of the data and of the methods he used. As with the model of the solar system in the Almagest, Ptolemy put all this information into a grand scheme. Following Marinos, he assigned coordinates to all the places and geographic features he knew, in a grid that spanned the globe. Latitude was measured from the equator, as it is today, but Ptolemy preferred in book 8 to express it as the length of the longest day rather than degrees of arc (the length of the midsummer day increases from 12h to 24h as one goes from the equator to the polar circle). In books 2 through 7, he used degrees and put the meridian of 0 longitude at the most western land he knew, the "Blessed Islands", probably the Cape Verde islands (not the Canary Islands, as long accepted) as suggested by the location of the six dots labelled the "FORTUNATA" islands near the left extreme of the blue sea of Ptolemy's map here reproduced.