Unequal hours, measured from sunrise and sunset
The planetary hours, the sāʿāt al-kawākib, are among the oldest ways of telling time by the sky. Each hour of the day and night is given to one of the seven planets, and the planet lends the hour its nature. This page sets out how the hours are reckoned, how the tradition used them, and how Canopy, a planetary hours app for iPhone and Android, keeps them in view.
The hours in question are not the sixty-minute hours of a clock. The astronomers called them temporal or seasonal hours, al-sāʿāt al-zamāniyya: the time from sunrise to sunset is divided into twelve equal parts, and the time from sunset to the next sunrise into twelve more. Day hours and night hours are therefore almost never the same length, and neither stays fixed through the year.
A worked example makes this plain. At a mid-northern latitude near midsummer, the Sun may stand above the horizon for about fifteen hours. Fifteen hours divided by twelve gives day hours of seventy-five minutes, while the nine hours of darkness give night hours of forty-five. Near midwinter the figures reverse. At the equinoxes day and night are close to equal, and every hour comes near sixty minutes; close to the equator the hours stay near sixty minutes all year. In the far north, where the Sun may not set or rise for weeks, the method has no sunrise to count from at all.
Because the reckoning begins at the horizon, small choices matter. Whether sunrise is taken at the Sun's upper edge or its center, and how the bending of light near the horizon is allowed for, can move the start of an hour by a few minutes. That is why two tables for the same place may disagree slightly.
The Chaldean order, the day ruler and the planets of the weekdays
The hours take their rulers in a fixed sequence known as the Chaldean order: Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon. It runs from the slowest planet to the swiftest, which ancient astronomy also read as the order from the highest sphere to the lowest: from Saturn, whose revolution through the zodiac takes about twenty-nine and a half years, down to the Moon, which goes round in about twenty-seven days. After the Moon, the sequence returns to Saturn and begins again.
The hour that opens each day, at sunrise, belongs to the planet that rules the day, and the hours that follow run on through the Chaldean order. Take Thursday, Jupiter's day: its hours run Jupiter, Mars, the Sun, Venus, Mercury, the Moon, Saturn, and then Jupiter again in the eighth hour. The thirteenth hour, the opening hour of the night, falls to the Moon, and the twenty-fourth to the Sun. The next hour in the sequence is Venus, and so Friday dawns on Venus. In this way the hours bind the week days and planets together: each day takes as its lord the planet of its first hour after sunrise, so Sunday belongs to the Sun, Monday to the Moon and Saturday to Saturn.
Since twenty-four hours carry the count three steps further around a cycle of seven, each day's ruler stands three places on from the last: Saturn, the Sun, the Moon, Mars, Mercury, Jupiter, Venus. This is the planetary week, and it still sits in the names of the days in many European languages. The Roman historian Cassius Dio, writing in the third century, already gave the hours as one explanation of it. The Arabic week, by contrast, simply counts its days, al-aḥad, "the one", al-ithnayn, "the two", and so on, keeping separate names for al-jumʿa, the day of gathering, and al-sabt, the sabbath; the astrologers nonetheless gave each of those days its planetary lord.
One consequence is easily missed. The planetary day runs from sunrise to sunrise, not from midnight, so the hours after dark belong to the day that began that morning. The small hours before Friday's dawn are still Thursday's, by this reckoning.
Animals of the hours, planets of the hours
Chinese astrology gives the same kind of office to its twelve animals, from the Rat to the Pig, which rule not only years but months, days and hours. The almanac names an animal for every day as its sixty-day cycle turns, a Chinese daily zodiac quite apart from the animal of your birth year, and it divides the whole day into twelve double-hours of two clock hours each, one for each animal.
The planetary scheme differs in two ways. Its rulers are the seven planets rather than twelve animals, and its hours are unequal, counted from local sunrise and sunset, so they stretch and shrink with the seasons where the double-hours keep to the clock. The readings differ as well: if you read a Chinese horoscope daily, it is keyed to the animal of your birth year and how it meets the animal of the day.
The two reckonings did meet. Buddhist astrology spread the seven-day planetary week through Tang China in the eighth century, set out in the monk Amoghavajra's Xiuyao jing, and calendars in China and Japan came to mark each Sunday with the character mì, borrowed from the Sogdian name of the Sun's day. The lords of the days there were the same seven planets, in the same order, that rule the week here.
Canopy casts no Chinese chart and gives no animal signs. It reads each day from the sky over you instead: the planet ruling the day and the present hour, reckoned for where you are, the Moon's mansion, and the day's transits to your own chart.
What each hour was used for
In the tradition, each hour falls under the planetary influence of its ruler, which lends the hour its own significations, and a matter was thought to sit well in the hour of a planet whose nature suits it. Al-Bīrūnī sets out the lords of the days and the hours in his Book of Instruction (al-Tafhīm, 1029), alongside the rest of the curriculum of the art.
The broad associations are long-standing. The hour of Jupiter was held suitable for matters of law and religion, for petitions, and for whatever one hopes to see increase. The hour of Venus belonged to love and friendship, to music, ornament and pleasure. Mercury's hour suited writing, study, reckoning and trade; the Moon's, journeys, messages and the business of the people; the Sun's, dealings with rulers and those in authority. The hours of the two malefics were approached with care: Mars's for matters of fire, iron and contest, Saturn's for what is meant to be slow and lasting, and generally avoided for new beginnings.
The handbooks of talismanic practice leaned on the hours heavily. The Picatrix (Ghāyat al-Ḥakīm) repeatedly ties a work addressed to a planet to that planet's day and hour, so that the day ruler and the hour ruler agree. For the practitioner the hour was a way of aligning a small human act with the larger order of the sky, a practice of attention and timing rather than a promise of any particular result.
Planetary hours and lunar mansions in electional timing
In the electional manuals, the hour is one consideration among several. Choosing a time to begin something, the art of electional astrology or ikhtiyārāt, also asks after the condition of the Moon, the mansion she occupies, the rising degree and its lord, and the dignity of the planets that signify the matter. A favorable hour under an afflicted Moon was not counted a good election.
The Moon's station is the natural companion to the hour. Where the hour changes roughly every hour, the Moon holds each of the twenty-eight lunar mansions for about a night, so the mansion sets the wider weather and the hour the finer grain within it. Talismanic work joins the two again, together with the rising and culmination of particular fixed stars, as described under talismanic timing.
The hour of Venus and the timing of love
Of the seven planets, Venus is the one the tradition gave to love, and her hours come often. Friday is her day, so the first hour after Friday's sunrise is hers; and because the hours pass through the seven planets in turn, she returns every seventh hour, three or four times in every twenty-four hours. On Friday she holds the first, eighth, fifteenth and twenty-second hours.
The hour was chosen for the matter, not for the person. There is no separate hour for Aries love or for any other sign: courtship, affection and celebration went to Venus whatever the signs of the people involved.
When Venus holds the present hour, Canopy's counsel turns to love, beauty and harmony, to romance, art and gatherings. For a larger beginning, three of Canopy's elections are kept for love: Planning Romantic Dates, Proposals & Engagements and Wedding Day & Marriage each search the dates you set, weighing the ruler of the hour together with the Moon and her mansion. The love you bring to the hour is read in your natal chart, from Venus, the Moon and the Lots of Eros and Marriage, two of the ten Arabic lots Canopy computes.
How Canopy keeps the planetary hours
Canopy tells you which planet rules the present hour, and its counsel, through every hour of day and night. Each day's reading takes its tone from the day's ruler and is drawn from the sky over your location and from your natal chart, and beneath it the Sun, the Moon and the day's ruler are shown in the signs and degrees they hold today.
Canopy also carries the angels of the hours, in two registers. The first gives an angel to each pairing of the day's ruler with the hour's ruler, forty-nine in all, and Canopy shows it with the present planetary hour. The second, older register gives each of the twenty-four hours of every weekday its own keeper, and Canopy shows the keeper of the hour of your birth in your chart. Each lunar mansion has its own angel as well.
The hour matters to the electional tools too. When Canopy scans the sky for a window favorable to your intention, it weighs the ruler of the hour: some hours are favored for a given matter and others counted hostile, and an hour whose lord is retrograde or combust counts against the window. Every reading is drawn from classical sources.
Home Screen widgets keep the day and the planetary hour in view, or the day, the hour and the mansion together, without opening the app. Canopy is available on iPhone from the App Store and on Android from Google Play.
Questions
How are planetary hours calculated?
Take the time from sunrise to sunset and divide it by twelve to find the length of a day hour; do the same from sunset to the next sunrise for the night hours. The hour after sunrise belongs to the planet ruling the weekday, and each hour after it takes the next planet in the Chaldean order: Saturn, Jupiter, Mars, the Sun, Venus, Mercury, the Moon, then round again.
Why aren't planetary hours sixty minutes long?
They are seasonal hours, twelve to the day and twelve to the night, so their length follows the length of daylight. In summer the day hours stretch and the night hours shrink; in winter the reverse. At the equinoxes, and close to the equator, they come near sixty minutes. The further from the equator, the greater the difference between summer and winter.
Do planetary hours start at sunrise or midnight?
At sunrise. The planetary day runs from one sunrise to the next, and its opening hour belongs to the day's ruler: the Sun on Sunday, the Moon on Monday, and so on. The hours after sunset, and the small hours before the following dawn, still belong to the day that began that morning.
Do planetary hours depend on where you live?
Yes. Unlike a horoscope written for everyone born under one sign, the hours are reckoned from local sunrise and sunset, so the hours near you begin and end at different clock times from those in a city a few hundred miles away. Canopy computes them for your location.
Is there a horoscope near me, worked out for where I actually am?
As near as astrology gets: the planetary hour belongs to one particular place, because it is counted from that place's own sunrise and sunset. Canopy reckons the hours, and the windows its elections find, for the location you set, either where you are now or a place you search for, such as a city you are about to visit, and a Home Screen widget keeps the present hour in view.
Can I get an astrocartography chart calculator free in Canopy?
Canopy does not draw astrocartography maps at all. That is a twentieth-century technique, which traces across the globe the places where each planet of a birth chart would have stood on one of the four angles. The older astrology joined place and sky in other ways: Ptolemy's Tetrabiblos assigned regions and peoples to the signs, and the angles of any chart, like the planetary hours, change from place to place. For a move itself, Canopy's Travel & Journeys election, made for trips, pilgrimages and relocations, favors the Moon in a moveable sign and sets aside any window with Mars or Saturn in the seventh house.
Which planet rules each day of the week?
Sunday belongs to the Sun, Monday to the Moon, Tuesday to Mars, Wednesday to Mercury, Thursday to Jupiter, Friday to Venus and Saturday to Saturn. Each day is ruled by the planet of its first hour at sunrise, and the names still show it: English keeps the Sun, the Moon and Saturn in Sunday, Monday and Saturday, and French keeps Mars, Mercury, Jupiter and Venus in mardi, mercredi, jeudi and vendredi.
Why don't the week days and planets follow the Chaldean order?
Because a day holds twenty-four hours, and twenty-four hours carry the count three places further around the cycle of seven, so each sunrise falls to the planet three places along from the last: Saturn, the Sun, the Moon, Mars, Mercury, Jupiter, Venus. Set the seven planets around a circle in the Chaldean order and join each to the planet three places further on, and the lines trace the week as a seven-pointed star.
Why does the Chaldean order begin with Saturn?
Because Saturn is the slowest of the seven traditional planets. Saturn's revolution through the zodiac takes about twenty-nine and a half years, Jupiter's about twelve and Mars's about two, while the Sun goes round in a year and the Moon in about twenty-seven days. Venus and Mercury, which never stray far from the Sun, were placed between the Sun and the Moon, and ancient astronomy read the whole sequence as the order of the spheres, from Saturn's, the highest, down to the Moon's.
Is there astrology for world events, or only for people?
There is, and the Arabic authors practiced it as mundane astrology, judging peoples and dynasties from eclipses, from the Sun's yearly entry into Aries, and from the conjunctions of Saturn and Jupiter, which meet about every twenty years; Abū Maʿshar's Book of Religions and Dynasties is its classic text. Canopy keeps to the personal branches of the art and makes no forecasts for nations or the world, though its Day & Week Ahead names the sky's shared events as they fall: new and full Moons, eclipses, and planets stationing retrograde or direct.
What was a Jupiter hour or a Venus hour used for?
The tradition held Jupiter's hour suitable for matters of law, religion, petitions and increase, and Venus's hour for love, friendship, music and adornment. Mercury's hour was given to writing, study and trade, and the Sun's to dealings with those in authority. These are historical associations, read for reflection and timing, not promises of an outcome.
Does Canopy have a daily love scope or a daily sexscope?
Not one written for a sign. Each day's reading in Canopy marks Love among its life areas as Favorable, Neutral or Caution, from the day's transits to your own natal chart, with Venus and the Moon as its significators. When the Moon crosses your Lot of Eros or your Lot of Marriage, the reading says so and shows the next crossings ahead, and through the day Canopy names the ruling planetary hour, so you can see when Venus has the hour.
Is there a Gemini single love horoscope for today?
Not in the Sun-sign sense: a horoscope written for every Gemini cannot see your own Venus, your seventh house or where today's Moon falls in your chart. Canopy reads today's sky against your natal chart, marks whether Love is favorable, and names the hour of Venus when it arrives. For a first meeting, its Planning Romantic Dates election searches the dates you set for the strongest windows; and if you would rather write first, the tradition gave the hour of Mercury, Gemini's own lord, to writing.
Can a Capricorn horoscope for money today tell me when to act?
Only in the broadest way, since it is written for everyone born with the Sun in Capricorn. The tradition timed money matters by the hour instead, Jupiter's for increase and Mercury's for trade and reckoning, and Canopy names the ruler of the present hour, reckoned from your own sunrise and sunset. For a larger decision, its Investments & Financial Decisions election searches any span of up to 183 days and favors windows in the hours of Jupiter, Mercury and the Sun.
Are planetary hours enough on their own for electional timing?
Not in the classical practice. The manuals treat the hour as one layer of an election, weighed together with the condition of the Moon, her lunar mansion, the rising degree and the dignity of the planets involved. A well-chosen hour under an afflicted Moon was not considered a sound beginning. See electional astrology for the wider method.
Do I need a horary calculator to find the planetary hour?
No. The hour needs only the weekday and the times of local sunrise and sunset, and Canopy names the ruler of the present hour for your location, though it does not cast horary charts. Horary astrologers did weigh the hour: William Lilly, writing in 1647, held a question fit to judge when the lord of the hour and the lord of the Ascendant were the same planet, of one triplicity, or of one nature.
Did astrologers find the planetary hour with an astrolabe?
Often, yes. Many astrolabe plates carry lines for the twelve unequal hours, drawn below the horizon: with the rete set for the moment from the measured altitude of the Sun or a star, the point opposite the Sun's degree fell among those lines by day, and the Sun's own degree by night, showing the seasonal hour directly. The same setting gave the bones of an astrolabe astrology chart, the degree rising in the east and the degree at the Midheaven, as the guide to Arabic astrology describes; Canopy works the hour out for your location without the instrument.
Does Canopy have a snake daily horoscope or a horse daily horoscope?
No; Canopy does not read the Chinese animals, and their day is divided differently in any case. The Snake's double-hour runs from nine to eleven in the morning and the Horse's from eleven to one, centered on noon by the clock, while planetary hours keep no fixed clock times: each is counted from your own sunrise, and the sixth hour of the day gives way to the seventh at solar noon, whatever the season. What Canopy reads each day is the planet ruling the day and the present hour, with tonight's lunar mansion and today's transits to your natal chart.
Does Canopy have a daily rat horoscope or a dog daily horoscope?
No, Canopy keeps to the planets, though the Rat and the Dog have hours of their own: the Rat's double-hour, first of the twelve, runs from eleven at night to one in the morning, and the Dog's from seven to nine in the evening. The almanac also sets each animal against the one six places away, the Rat against the Horse and the Dog against the Dragon, much as the Arabic astrologers read the opposition, six signs apart, as an aspect of enmity. By the planetary reckoning the hours around midnight still fall within the day that opened at the last sunrise, and Canopy reads that day by its ruling planet, the planet of the present hour and the transits to your own chart.
Does Canopy have a complete Chinese zodiac calculator?
No. A Chinese birth chart sets out four pillars, the year, month, day and double-hour of birth, each pairing an animal with an element; Canopy casts the Arabian natal chart instead. From your birth date, time and place it draws up a chart in the tropical zodiac with whole-sign houses, essential dignities, ten Arabic lots and the almuten, and, when your birth time is known, it finds the planetary hour you were born in and names the angel set over it, much as the Chinese chart keeps a pillar for the hour.