What the Moon sign is
Your Moon sign is the sign of the zodiac the Moon occupied at the moment you were born. The Moon is the fastest body astrologers use: it moves about 13° a day and passes through the whole zodiac in a little over 27 days, so it spends only two and a half days or so in each sign. That makes the Moon sign more individual than the Sun sign, which everyone born in the same month or so shares.
Astrologers read the Moon as the emotional life: needs, moods, habits, what makes a person feel safe, and how they care for others and want to be cared for. Traditional astrology also gives the Moon the body, the mother and the ordinary run of daily life. The note under the chart gives a short traditional reading of your Moon sign; the notes for your Sun and rising sign follow it. Each sign also has a longer page of its own, listed under the Moon in each sign further down.
When birth time matters for the Moon
For most planets the birth time hardly matters — they move a degree a day or less. The Moon is different: over a day it covers 12° to 15°, roughly half a sign. On a little more than half of all days it stays in one sign from midnight to midnight, and the date alone settles your Moon sign. On the others it moves into the next sign at some hour, and then the time decides.
If you don’t know your birth time, tick the box: the calculator casts the chart for noon and shows the range the Moon covered that day. When the range stays inside one sign, that is your Moon sign whatever the time. When it crosses a boundary, the headline gives both signs, and the notes describe both, marked earlier and later that day. Knowing roughly whether you were born in the morning or the evening is often enough to choose.
Western Moon sign and Vedic Rashi
The switch under the chart changes the zodiac. Western is tropical: the signs are measured from the spring equinox, so 0° Aries is where the Sun stands at the March equinox. Vedic is sidereal: the signs are measured from the stars, using the Lahiri ayanamsa, which now puts the sidereal zodiac about 24° behind the tropical one. The Moon doesn’t move — only the reference point changes — but in about four cases out of five the Vedic Moon lands one sign earlier.
In Jyotish the Moon’s sign, the Rashi, carries more weight than the Sun’s. Indian horoscope columns are written by Moon sign, and many traditional choices, from a child’s name to the timing of ceremonies, are made from the Moon’s position. The Vedic view also shows the chart in North Indian style, the Moon’s nakshatra and the current Vimshottari dasha, which starts from it. Each of the twelve Rashis has a page of its own in the Rashi guides.
Your birth nakshatra
Besides the twelve signs, Jyotish divides the zodiac into 27 nakshatras, lunar mansions of 13°20′ each, very close to the distance the Moon travels in a day. Each nakshatra has a ruling graha, a deity and a character of its own, and is split into four padas of 3°20′. Your birth nakshatra, the janma nakshatra, is the one the Moon was in at birth. It sets the order of the Vimshottari dasha — the first period belongs to its lord — and it is the basis of traditional horoscope matching.
Because the Moon crosses a whole nakshatra in about a day, the nakshatra needs the birth time more than the Rashi does. Without a time the calculator shows the nakshatra at noon and says so.
The Moon in a horary chart
A question chart reads the Moon less as a temperament than as the course of the matter. In horary she is the co-significator of the person asking, and her course through the rest of her sign describes how the matter unfolds: her next applying aspect — the next planet she will reach by sextile, square, trine, opposition or conjunction — shows what happens next. When she will reach none before she leaves her sign, most horary astrologers today call her void of course; older authors measured it by orbs rather than by the sign’s end. Either way the warning is old: William Lilly’s Christian Astrology (1647) says that while she is void, matters go hardly on unless the main significators are strong.
The AstroGPT app follows the Moon in this sense. Its chart is the sky at the minute you begin a chat and ask your question, at your location, so the Moon it reads is that moment’s Moon, never your natal one. The horary astrology guide shows how her aspects are read.
Everything here is offered for reflection and entertainment.