[EMAIL PROTECTED] wrote: > .... > I am curious about one thing though. I've never heard of planetary hours. > What are they, and what is their use? ....> > Charles Gann > > **************************************** > * Sundials and The Author * > * http://www.geocities.com/athens/1012 * > ****************************************
Charles, In both older and newer books and articles many times the meaning of planetary hours is the same as for antique or unequal hours, the day from sunrise to sunset devided in 12 hours. Long hours in summer, short hours in winter, but equal in one day. These antique hours are based on the arc of one day, not on a great circle in the sphere. But Joseph Drecker, Germany, wrote in 1925 in another way. He quoted a Latin sentence by Sacrobosco. ( about 1230) Hora naturalis est spatium temporis, in quo medietas signi peroritur. These 'natural hours' should be the planetary hours, according to Drecker. So defined an hour is the time that is needed for 15 degrees of the ecliptic to rise above the horizon. There are always 6 signs above the horizon, that is 12 times 15 degrees, so there are 12 planetary hours in one day from sunrise to sunset. ( this number thus equals the antique hours ) The rise of a complete sign ( or the half of it ) is very irregular, not only seasonaly, but also dayly. Sometimes this happens 'fast', another time this happens 'slow'. Therefore the planetory hours in one day too are very irregular. ( this differs from the antique hours, they are in one day all equal ) These hours are based on a great circle as the ecliptic is. This is more natural as Drecker wrote. I don't know of any use of these hours. Perhaps they are or were usefull in astrology? But historicaly they are interesting. Fer.
