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Planet Clock Applet
Planetary (Unequal) Hours Calculator

Check your time zone offset and the local time.


Click the applet first!
Enter latitude in decimal degrees
(southern negative),
enter longitude in decimal degrees
(western negative),
then press the button Apply input.

You may use the keys "y", "m", "d", "h", "n" to increase the year, month, date, hour, minute, or Shift key and "y", "m", "d", "h", "n" to decrease the year, month, date, hour, minute !

Press the button "Planetary Clock":

plnanet hous

Applet: Quadrans Vetus

The planetary hours (also called unequal hours, Jewish hours, Italian hours) are an ancient system in which one of the seven traditional naked eye planets is given rulership over each day and various parts of the day. Monday is always the Day of the Moon. Tuesday is the day of Mars, Wednesday is ruled by Mercury, Thursday is Jupiter's day, Friday is the day of Venus, Saturday is the day of Saturn, and Sunday is the day of the Sun.

Each planetary day begins at sunrise, and ends at the next day's sunrise. For example, Sunrise on Saturday is the beginning of the day of Saturn. Before sunrise on Saturday, you are still under the day of Venus.
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.
The first planetary hour of the day is always the same as the planetary day; so sunrise on Monday is the beginning of both the day of the Moon and the hour of the Moon. The hours repeat infinitely in this order:
Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon
So the second planetary hour of the day of the Moon is the hour of Saturn, the third would be the hour of Jupiter, and so on.
(from: http://en.wikipedia.org/wiki/Planetary_hours)

Example: Berlin, 52.51° N, 13.41° E:

Planetary Hour
Planetary Hour
Mar 20
Sep 21
61 min 59 min
Jun 21
84 min 36 min
Dec 21
38 min 82 min

The Canonical Daytime Hours:

first hour
third hour Terce
sixth hour (noon)
ninth hour None
twelvth hour Vesper

The Astronomical Clock in Münster

astronomical clock munster

Münster, 51.97° N, 7.63° E
Fr, 2008 September 5

astronomical clock applet

 at 12:30 local time (CEST):
6 th hour of the day
ruler of the hour is Mars
ruler of the 1 st hour, and ruler of the day, is Venus

planetary hour
          planet ruler

planetary hour

Web Links

Planetary Hours (JavaScript)

The Uses of History in Science Education

Hours and hours

Canonical hours (Wikipedia)

Last Modified: 2023, Oct 06

© 2008-2023 Juergen Giesen