The first thing to know about Chinese Lunar Calendar
The Chinese calendar combines lunar and solar system together. Most of people think that YEAR and DAY cycle use solar system and MONTH cycle uses lunar system. Actually, DAY uses Stem-Branch 60-day cycle system. And the name of the MONTH uses solar system. The Chinese solar months are not like those months in the modern calendar. The Chinese calendar divides the year into 24 solar segments by the Sun positions on the tropical zodiac. It's similar with western Astrology. Each segment has its name for ancient farmers use. It's much easier to understand the whole picture by studying the following chart.
|Start of Spring||315||1 - Tiger|
|Excited Insects||345||2 - Rabbit|
|Clear and Bright||15||3 - Dragon|
|Start of Summer||45||4 - Snake|
|Grain in Ear||75||5 - Horse|
|Slight Heat||105||6 - Sheep|
|Start of Autumn||135||7 - Monkey|
|White Dew||165||8 - Chicken|
|Cold Dew||195||9 - Dog|
|Start of Winter||225||10 - Pig|
|Heavy Snow||255||11 - Rat|
|Little Cold||285||12 - Cow|
The solar months are divided by the sun longitudes. The first month, tiger month, begins from "Start of Spring" Segment or When the sun enters 315 degree on the tropical zodiac. The second month, rabbit month, begins from "Excited Insects" Segment or When sun enter 345 degree on the tropical zodiac. The beginning of a solar month is called Segment Point. In the middle of a solar month is called Center Point. For example, the segment of "Rain Water" and "Vernal Equinox" are Center Points. The astrology name of "Pisces" and "Aries" are Center Points.
The new moon day is the first day of a lunar month. The length of a lunar month is the length between two new moon days. The name of a lunar name is named by the Solar Center Point. For example, If a lunar month contains the "Rain Water" Center Point is the first month of lunar calendar, as known as tiger month.
If a lunar month does not contain any Solar Center Point, we assign that month as a Leap Month. The name of the leap month is named as previous lunar month. The reason to assign a leap month is that we want the Moon cycle to match up the Sun cycle.
The book and software of the Chinese Fortune-Telling Calendar follow these three rules which ancient Chinese made it thousand years ago.
Most of people confuse about the solar months with lunar months. They think all Chinese Fortune-Telling system are using lunar months. Actually, the Fortune-Telling system called Eight (8) Characters only uses the solar month. The other popular system called Dipper uses solar month and lunar month together.
The complete discussion of the Chinese Lunar Calendar is in the content of Chinese Lunar Calendar CD, which provide you the Sun and Moon astronomical data from 1 to 2246 A.D. and the sample Visual Basic programs to do the Lunar Calendar conversion.