Tuesday, February 9, 2010

Egyptian Planetary Hours and Oddities of Time Keeping

Anyone who has worked planetary or astrological magick has faced the difficult task of attempting to use the archaic and peculiar planetary hours. Many modern books have tables of the planetary hours, and the sources for these tables are the older grimoires and books, such as Agrippa’s Occult Philosophy. Needless to say, the typical system of planetary hours uses the seven planets of the ancients (actually five planets, the Sun and Moon) and divides the day into 12 hours of daylight and 12 hours of night, with the planet associated with the day of the week beginning the list. The order of planets is always some variation of Moon, Saturn, Jupiter, Mars, Sun, Venus and Mercury (called the Chaldean sequence). The planetary association of the days of the week are Monday = Moon, Tuesday = Mars, Wednesday = Mercury, Thursday = Jupiter, Friday = Venus, Saturday = Saturn and Sunday = Sun. At dawn of each of these days of the week, the planetary hour is always the same as the day. Interestingly enough, if you overlay these seven planets on the grid of 24 hours, starting with the planetary hour of that day, then the 25th hour will be exactly the planetary hour of the next day of the week.

Many magicians who bother to use the planetary hours employ the mechanism of variable length hours to accommodate the actual length of the day or night. Obviously, around the Winter Solstice, the hours during the day will be shorter than the hours of the night, and correspondingly, around the Summer Solstice, the duration of the hours of the day will be longer than the hours of night. This is an age old conundrum that was fixed by the Greeks, most notably Hipparchus (190 - 120 BCE), who proposed establishing hours of equal duration despite the time of the season, which became known as equinoctial hours, a system that we use today.

Equinoctial hours were also used earlier by the ancient Akkadians, and this system was based on the duration of the hour at the time of the vernal or autumnal equinoxes, when the period of day and night were equal. However, it was not until the advent of clocks that the equinoctial hour became the standard. I have chosen to use the equinoctial hour system in how I work with the planetary hours, establishing the first hour of the day by the exact moment of the sun rising locally over the horizon, and then proceeding to assign the planetary hours for the next 23 hours from that point in time, ignoring the need to divide the day and night into 12 variable hours. Some would dispute this methodology as not being traditional, and I would agree, but it is a simple and tidy approach to assigning planetary hours.

Thinking about this topic leads one to puzzle over other questions as well. Such as, how the ancients come up with 12 hour days if they didn’t have an accurate method of measuring time? Where did the number 12 come from, and how did they determine that there were 24 hours in the day? If the clock was not invented until the early 14th century, then there would not have been a mechanical methodology to measure time. Even the earliest clocks that first showed a dial (although they only had one hand to measure the hour) had a numbering system that showed 12 hours. Where did that come from and how was it developed? An interesting question, and one that I decided to examine for myself.

What started me on this track of research is when I came across a passage  in the book "Magic, Mystery, and Science - The Occult in Western Civilization" by Dan Barton and David Grandy, (Indiana University Press 2004). That passage said that the Egyptians used the decans (and their associated godheads and marking stars) to determine and qualify the hours of the night sky. During the night, the decan that appeared at the ascendant would tell the Egyptians what time it was. A decan would last approximately 40 minutes, so for each night (since Egypt experiences nearly year round 12 hour days and night) 18 of the 36 decans would be revealed, and during the changing of the seasons, the evening would potentially begin with a different decan over time, passing through the whole zodiacal wheel during an annual period. So there were magical hours used during the night, but these would have lasted 40 minutes instead of 60, and each decan would have been accorded a different minor godhead and quality, not to mention the 12 gates of the diurnal solar boat transit through the underworld. Of course this discovery sort of threw a monkey wrench into the whole concept of measuring hours, particularly planetary hours. So I must admit that I was quite intrigued.

Further study helped me clarify my thoughts about the astrological decans. So maybe we should take a quick trip down the allegorical time line and see how the measurement of time evolved.

Human beings, like most animals, function in what is called a diurnal cycle of night and day, sleep and wakefulness. The apparent motion of the sun makes it appear that it rises in the morning until it reaches a point nearly directly overhead, and then slowly moves lower in the sky until it sets below the horizon. Night time seems nearly seamless, with only the stars and the moon to determine the changing time. There would seem to be naturally four periods to the entire cycle of the day - dawn, noon, sunset and night. Some time around 3,000 BCE the Egyptians began making obelisks that would capture the variations of the daily and seasonal positions of the sun. Some of the obelisks had markings for the position of the sun at the two solstices. Later on, the Egyptians developed sun dials that used a “gnomon”, stylus or pointer to produce a shadow that indicated the time against a dial that marked the hours. Interestingly enough, there were 12 divisions or hours in the day, with the first and last hour being determined by sight alone, since the sun would not likely produce a sharp shadow against the dial during twilight. So the Egyptians had somehow decided on dividing the day into 12 hours using a sun dial to aid in that measurement.

It would also seem that the Egyptians used a system of reckoning when attempting to determine the hours at night, using the decans passing over the horizon as a kind of clock. Since twilight would have made this reckoning impossible, there would have been 12 hours of night associated with the decans, since making this measurement would have required complete darkness. Dawning light would have also potentially interfered, so there would have been an hour and a half both before full night and before dawn when such reckoning would have been impossible.

A device called a merkhet (plumb line) was discovered, whose invention was late, probably around 600 BCE, which was used to determine the north-south axis. Two of these devices were set up in a specific measured line from each other, and the subject would observe the rising of the decan star between these two devices. It’s likely that this late tool was based on more primitive technology that was used to perform the same kind of siting.

“The Egyptians improved upon the sundial with a merkhet, the oldest known astronomical tool. It was developed around 600 B.C. and uses a string with a weight on the end to accurately measure a straight vertical line (much like a carpenter uses a plumb bob today). A pair of merkhets were used to establish a North-South line by lining them up with the Pole Star. This allowed for the measurement of nighttime hours as it measured when certain stars crossed a marked meridian on the sundial.”

The Egyptians also had a primitive water clock as early as 1,500 BCE, since one was buried with the pharaoh Amenhotep I.  However, the accuracy of such a device and how it was set up to measure hourly duration at night has not been determined. We might assume that it either measured the 40 minute hour of the decans, or maybe it divided the night up into 12 hours just like the day.

Another interesting thing about the decans is that every 10 days a new decan would appear at the horizon at the first observable hour of the night. It’s from this array of 36 decans, each lasting 10 days, that the Egyptians determined their solar based calendar, where the last decan coincided with the annual inundation of the Nile river. They had a yearly calendar of 36 decans with five days added to the end to make 365 days in all.

We seem to have answered most of our questions except the one about how the 12 hours of the day were determined. While the mathematical numbering system of 12, 60 and 360 was the invention of the Sumarians, and that their cultural heirs, the Akkadians, determined the 60 minute hour and the 60 second minute, they didn’t have the technology to measure these divisions of time. However, if we accept that the Sumerians came up with the use of the number 12 for the hours of day and night, then how did the Egyptians come up with this number? We would either have to propose a form of diffusion, where these ideas were transported to the Egyptians from Mesopotamia, or maybe there is a simpler reason.  I believe I found the answer on the internet and this is what it says:

“Until the arrival of clockwork, in the 14th century AD, an hour is a variable concept. It is a practical division of the day into 12 segments (12 being the most convenient number for dividing into fractions, since it is divisible by 2, 3 and 4). For the same reason 60, divisible by 2, 3, 4 and 5, has been a larger framework of measurement ever since Babylonian times.”

So it would seem that dividing the day into 12 hours facilitates the use of fractions, allowing for the day to be divided into segments and the hour itself to be stated in fractions. We still use this methodology when we talk about half hours and quarter hours. One could use the same fractions to divide the day up into half days, quarter days, and even the use of thirds. Using any other number would have made such divisions more cumbersome. What this means is that the hour is actually an arbitrary division of time, used because of its simplicity and efficiency. Later on clocks made the hour a fixed quantity, just like the minute and the second. I believe that this realization is a simple explanation as to the nature of time keeping and how it evolved. The Egyptians, who were not as good at mathematics or astronomy as the Sumerians and Akkadians, independently came up with a system of dividing the day into 12 hours. The whole system is quite arbitrary - a human invention.

However we, as occultists and magicians, choose to divide up the day and determine the planetary hours can be variable and even arbitrary, so long as the methods we use are employed consistently and competently. It also helps to explain how we use these divisions so others will know what we are talking about when discussing planetary hours.

Frater Barrabbas


  1. Great article, its something ive never thought about. For planetary workings I look at the day of the week instead of getting into the specifics of hours. But I am not a detail oriented person.
    I enjoy your blog!
    En Pax

  2. I thought the 12 hour system was from the Babalonians as they had a base-twelve numerical system. Could be wrong as it has been a while.

    I use the agrippa method as I use the 7 planet system rather than add the moderns.

  3. Interesting points you bring up. I have never found any astrological reason for the planetary hours as we have them today (12 hours of day, 12 of night). I like your other suggestions. Personally I work when the planet is above the horizon and through much experimentation have found this to work far better.

  4. Again, I found this article to be very well-researched, written and presented. Astrology is the Ancient science from which many other sciences issued, and when used to determine character of an individual, can be absolutely exact in the hands of a learned Artist of this science. And, of course, it is a main pillar in the Art and Science of MAGIA.

    Shem-ha-Meforasch means the NAME OF BRILLIANT FIRE and is considered to be the expanded NAME of the Tetragrammaton, as you have clearly indicated in the articles you've written on this page. The Stairs of Gold TAROT deck includes the names of the Shem-ha-Meforasch Angels for the lesser Arcana cards, but I haven't checked whether they align with the GD or Tropical ARIES derivation yet.

    Very interesting and educating article Fr Barrabbas. I look forward to reading many more of your well-researched esoterica.