Re: Copernican Revolution

[Gary Karshner <karshner@STMARYTX.EDU>]

Larry,
        My understanding is, that even though Copernicus used epicycles, his
models are easier to calculate. This is a controversial point among
historians who for a long while accused Copernicus of requiring more
epicycles then Ptolemy. An examination of the response of astronomers of
the period shows that even some non-copernicans used his derivations to
make their calculations because they were easier. The Tychonic system that
had quite a following around 1600 allowed the use of copernican
calculations with a fixed Earth so you could throw out Aristotle's universe
but keep his physics.
        The preface of De Revolutionibus mentioned in the radio show was not
written by Copernicus but a bishop friend, and almost apologizes for the
book. The show also gave the impression that Copernicus work is a hard
read. This is true of the mathematical parts but the whole first part is a
discussion of the advantages of the system and is a relatively easier read.
Little that was written during this period is an easy read for us because
of the great changes in style that have happened since then.

Gary

At 01:14 PM 2/19/00 -0700, you wrote:
> Historical question:  I thought Copernicus' heliocentric model was not
> initially any more accurate than Ptolemy's.  Didn't he even have to have a
> few epicycles himself?  Until Kepler?  (See
> <http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/ECText/ch02_txt.ht
> m#2.2.1.>.)
>
> Not according to NPR's "Math Guy" this morning:
> <http://www.npr.org/ramfiles/wesat/20000219.wesat.04.ram>.
>
> Larry
Gary Karshner

St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU