The zodiac & the lunar calendar
Clear guides on the zodiac systems, ayanamsha, and how the lunar calendar works.
What kinds of zodiac are there: a complete guide
A breakdown of all the kinds of zodiac: the tropical and the sidereal are astrological systems based on the ecliptic, while the Chinese, Celtic, Egyptian, Mayan and Slavic ones are independent cultural calendars. Includes the history, a comparison table and how the systems differ.
History of Planetary Hours: From Babylon to the Present Day
How the tradition of planetary hours evolved from Babylonian priests and Egyptian daily divisions through Hellenistic astrology, the Islamic world, and medieval Europe to modern applications. Chronology, key figures, and texts.
The types of zodiac system: tropical, sidereal and astronomical
Short answer: the zodiac comes in three types — tropical (by equinoxes and seasons), sidereal (by the fixed stars, shifted by the ayanamsha) and astronomical (by the real constellation boundaries of the IAU). A comparison table and a hint on which one to choose.
The Chaldean Order: Why Planets Follow This Sequence
Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon — this is the Chaldean order of the seven classical planets. Where did it come from, why is it in this order, how does it define the days of the week and planetary hours, and what do the Chaldeans have to do with it?
The zodiac before 500 BCE: from lunar stations to Babylonian omenology
What the Mesopotamian sky looked like before the birth of the classical zodiac: lunar mansions, the Enuma Anu Enlil and MUL.APIN catalogues, Babylonian omenology and the shift from the lunar calendar to the 12 signs of the ecliptic.
First Quarter Moon: Half Disc and Evening Moon
The short answer: first quarter is the phase when the right half of the disc is lit (Northern Hemisphere). The Moon is visible in the evening and sets around midnight — about one quarter of the way from new to full moon.
Full Moon Explained: Supermoon and Night Light
The short answer: full moon is the phase when Earth sits between the Sun and the Moon and the whole disc is lit. The Moon rises around sunset and usually stays up until sunrise.
Moon Illumination, Age and Distance: What the Numbers Mean
The short answer: illumination is the share of the visible disc lit by the Sun (0–100%); astronomical age is the time since new moon; distance is the kilometres to the Moon. These are different measures: they help describe the phase, position in the cycle and apparent size, but do not fully determine observing conditions.
Last Quarter Moon: Half Disc and Morning Moon
The short answer: last quarter is the phase when the left half of the disc is lit (Northern Hemisphere). The Moon rises around midnight and is visible in the morning — about three quarters of the way from new moon.
New Moon Explained: Why the Moon Disappears
The short answer: new moon is the phase when the Moon sits between the Sun and Earth with its lit half turned away from us. The disc cannot be observed, and clear moonless nights are usually the darkest of the month.
What Is the Moon Phase Cycle
The short answer: moon phases are how much of the Sun-lit half of the Moon we see from Earth. The full cycle (synodic month) lasts 29.53 days: from new moon through first quarter and full moon to last quarter.
12 zodiac signs and constellations: what's the difference
Short answer: there are 12 zodiac signs — equal sectors of 30° — and 13 constellations on the ecliptic. We explain the difference, provide a table of dates, and explain why the Sun doesn't 'switch' from sign to sign together with a constellation.
Where to find the full texts of "Enuma Anu Enlil" and "MUL.APIN"
Where to find the full texts of the two main Babylonian astronomical works: MUL.APIN (published in full) and Enuma Anu Enlil (published in parts). Printed editions, the open databases CDLI, Oracc and eBL, and practical search tips.
Why the Day is Divided This Way: How Planetary Hours are Calculated
A planetary hour is 1/12 of the daylight or 1/12 of the night. Why exactly 12, where sunrise and sunset come from, why hours are unequal, how the planetary sequence is built, and what happens during the polar day. A step-by-step calculation with an example.
All the ayanamshas: who created them, when and why
A detailed account of the forty-seven ayanamshas the site can compute: Vedic, Babylonian, Indian textual and star-based scales. For each — when it appeared, who authored it, which tradition uses it, and how it differs from the tropical zodiac.
Frequently asked questions about the Moon: phases, signs and observing
We collected what gets asked most: how the phase cycle works, what a lunar day is, how illumination differs from phase, and what the naked eye can show.
Retrograde planetary motion: what it is and what it is not
A retrograde stretch is when a planet appears to move backwards. We explain why it happens, which planets it really applies to, and why a retrograde Mercury lasts weeks rather than months.
Astronomical events of the month: how to observe them
Conjunctions, oppositions, quadratures and meteor showers — what these events are, when they happen and what you can really see without a telescope.
Why the Sun rises and sets at different times
Sunrise and sunset times depend on latitude, season and longitude. We explain why summer days are longer, how the axial tilt affects twilight, and what to make of the calculated times.
What ecliptic longitudes actually tell you
A planet's position on the sky is measured as an ecliptic longitude — an angle along the plane of Earth's orbit. We explain how to read the figures, what direct and retrograde motion mean, and why visibility depends on latitude.
Lunar and solar eclipses: how they differ
An eclipse happens when the Sun, Earth and Moon line up. We look at the difference between lunar and solar eclipses, why they do not happen monthly, and how to read the eclipse data on a day page.
Astrology and astronomy: the difference and where they meet
The zodiac, its signs and the astrological systems are not constellations. We explain the difference between astronomy and astrology, where the signs came from, and why they still only partly overlap the real constellations.
The Moon Gardening Calendar: Day Types and Rules
Short answer: the gardening calendar divides the zodiac signs not into good and bad days, but into five day types — roots, leaves, flowers, fruit and barren. The day type determines which work counts as appropriate on that day.
How to Read a Lunar Calendar: the Day Card Explained
Short answer: a row in a lunar calendar is not a single date but an interval with a lunar day number, its own start time, a phase and a zodiac sign. A row has six columns: date, number, day start, phase, sign and sign-ingress time; the values in them are independent of each other.
The Lunar Haircut Calendar: How the Rules Work
Short answer: the haircut calendar takes exactly one value — the zodiac sign the Moon stands in on that day — and maps it onto a “favourable, neutral, unfavourable” table. Neither the phase nor the lunar day number takes part in the rules.
The Lunar Timber Calendar: Sign and Waxing Moon
Short answer: the timber calendar is the only one of the three specialty calendars that combines two rules. The zodiac sign gives the base rating, and the lunar day number lowers it by one step during the waxing Moon.
Moonrise and Moonset: Why the Time Keeps Shifting
Short answer: the Moon rises later each following day because it shifts eastward against the stars. On average over a month that is about 50 minutes a day, but on individual days the shift runs from 6 minutes to an hour and a half. Over a synodic month a full day accumulates, so the moonrise moment runs through a full cycle in a month and returns to the same hour.
The Zodiac Across Cultures: From Babylon to China
Zodiac schemes existed in Babylon, Greece, India, China and among the Maya. Each culture divided the sky in its own way: solar constellations, stars, lunar cycles. A comparison table and an explanation of why there are so many zodiacs.
What Are Planetary Hours
The short answer: planetary hours divide daylight and night into 12 equal parts each, with every hour ruled by one of the seven classical planets in the Chaldean order. How the hours are calculated, how to find the ruler of the current hour, and why this is a tradition rather than a science.
Tropical and sidereal zodiac: what's the difference
The difference between the tropical and sidereal zodiac is in the reference point: the tropical zodiac starts from the vernal equinox and tracks the seasons, while the sidereal zodiac starts from fixed stars and is offset by about 24°. We explain with examples and a comparison table.
What to plan in each planetary hour: time selection for tasks
How elective astrology uses planetary hours: what the tradition advises doing in the hour of Saturn, Jupiter, Mars, Sun, Venus, Mercury, and the Moon, how daytime hours differ from nighttime ones, and how to combine the planet of the day and hour in practice.
What is ayanamsha in astrology
Ayanamsha is the angle of difference between the tropical and sidereal zodiac (about 24°). It shows how far the sidereal sign is shifted from the seasonal one. We explain it simply, with a list of popular ayanamshas.
Who are the Chaldeans: Astronomers and Astrologers of Ancient Babylon
The Chaldeans were priest-astronomers of ancient Babylon who created the first systematic astronomy: ephemerides, the zodiac, lunar cycles, and dividing the sky into 360 degrees. Learn why the Greeks called all astrologers 'Chaldeans' and how their knowledge reached us through planetary hours.
Who and Where Uses Planetary Hours: Traditions of Different Cultures
Planetary hours are a living tradition used in the Hellenistic world, the Islamic East, medieval Europe, and Jewish and Indian cultures. How each tradition applied the hours, where they spread, and what they look like today.