Editing Planetary hours (section)

{{Short description|Hours planets rule in a day}}
{{astrology}}
The '''planetary hours''' are an ancient system in which one of the seven   [[classical planets]] is given rulership over each day and various parts of the day. Developed in [[Hellenistic astrology]], it has possible roots in older [[Babylonian astrology]], and it is the origin of the [[names of the days of the week]] as used in English and numerous other languages.

The classical planets are  [[Saturn]], [[Jupiter]],  [[Mars]], [[Sun|the Sun]], [[Venus]], [[Mercury (planet)|Mercury]] and [[Moon|the Moon]], and they take rulership over the hours in this sequence.

The sequence is from slowest- to fastest-moving as the planets appear in the night sky, and so is from furthest to nearest in the [[planetary sphere]]s model.  This order has come to be known as the "Chaldean order".<ref>
    The term "Chaldean order" is modern, used e.g. in ''Popular Science'', January 1895, [https://books.google.com/books?id=zyIDAAAAMBAJ&pg=PA335 p. 335], but there is no evidence this order is actually taken from [[Babylonian astrology]]; rather, it seems to be a Hellenistic innovation of the 2nd century BC; see Eviatar Zerubavel, ''The Seven Day Circle: The History and Meaning of the Week'',  University of Chicago Press, 1989 [1985],
[https://books.google.com/books?id=Cd5ZjRsNj4sC&pg=PA14 p. 14].
</ref>

[[File:Heptagram of the celestial bodies of the weekdays.png|thumb|right|Diagram showing the relationship between the Chaldean order of the [[classical planets]] (outer circle) and the order of the days of the week (heptagram)]] 
As each day is divided into 24 hours, the first hour of a day is ruled by the planet three places down in the Chaldean order from the planet ruling the first hour of the preceding day;<ref>The complete cycle of seven planets occurs three times in the day, occupying 7x3=21 hours.  The day’s remaining three hours take the first three planets of the next cycle.</ref> i.e. a day with its first hour ruled by the Sun ("[[Sunday]]") is followed by a day with its first hour ruled by the Moon ("[[Monday]]"), followed by Mars ("[[Tuesday]]"), Mercury ("[[Wednesday]]"), Jupiter ("[[Thursday]]"), Venus ("[[Friday]]") and Saturn ("[[Saturday]]"), again followed by Sunday,<ref>The day is divided into two parts; the day (time between sunrise and [[sunset]]) and the night (time between sunset and tomorrow's sunrise).  Each part of the day is then divided into 12 equal parts, for a total of 24 (unequal) hours.
The further the location is from the [[equator]]; and the closer the date is to the [[solstices]] (as opposed to the [[equinoxes]]); the greater the difference in length between the length of the planetary hours and the clock hours.
{{Cite book |last=Barrett |first=Francis |author-link=Francis Barrett (occultist) |title=[[The Magus (handbook)|The Magus]] |orig-year=First printed in 1801 |edition=First Carol Publishing Group |date=1989 |publisher=Carol Publishing Group |location=New York |pages=139–140 |chapter=Book II. Part IV. The Magic and Philosophy of Trithemius of Spanheim |chapter-url=http://www.sacred-texts.com/grim/magus/ma251.htm |isbn=0-8065-0462-5}}
</ref> yielding the familiar naming of the [[days of the week]].