Chandrashtama: what it is, how long it lasts, and how to find yours
Chandrashtama is the couple of days each month when the Moon passes through the eighth sign from your Moon sign. It is a reason to put off big beginnings, not a day to fear. Here is how it is counted and how to find your dates.
Chandrashtama is one of the few things in a weekly horoscope that is actually calculated. It is the stretch, roughly two and a quarter days each month, when the Moon passes through the eighth sign from your own Moon sign. Tradition advises caution during it. What tradition does not say is that it is a bad day in any dramatic sense, and that difference is what this article is about.
The name explains itself. Chandra is the Moon and ashtama means eighth.
What Chandrashtama is
You need one fact from your birth chart: your Moon sign (rashi), the sign the Moon was in when you were born. Count that sign as the first and keep counting forward through the zodiac. The eighth sign you reach is your Chandrashtama sign. Whenever the Moon is passing through that sign, you are in Chandrashtama.
Here is the count for every rashi:
| Your Moon sign | Chandrashtama when the Moon is in |
|---|---|
| Mesha (Aries) | Vrischika (Scorpio) |
| Vrishabha (Taurus) | Dhanu (Sagittarius) |
| Mithuna (Gemini) | Makara (Capricorn) |
| Karka (Cancer) | Kumbha (Aquarius) |
| Simha (Leo) | Meena (Pisces) |
| Kanya (Virgo) | Mesha (Aries) |
| Tula (Libra) | Vrishabha (Taurus) |
| Vrischika (Scorpio) | Mithuna (Gemini) |
| Dhanu (Sagittarius) | Karka (Cancer) |
| Makara (Capricorn) | Simha (Leo) |
| Kumbha (Aquarius) | Kanya (Virgo) |
| Meena (Pisces) | Tula (Libra) |
These are sidereal signs, the ones Vedic astrology uses, and we work them out with the Lahiri ayanamsa. They are usually not the same as the Western star sign you see in a magazine. That one comes from the Sun, not the Moon, and it is measured against a different zodiac. If you grew up in London or New Jersey thinking of yourself as a Leo, your Moon sign could be almost anything.
How long it lasts and how often
The Moon moves faster than anything else in the sky. It goes round all twelve signs in a little under a month, so it spends about two and a quarter days in each one. That is how long each Chandrashtama lasts.
Because the Moon takes slightly less than a calendar month to go round, Chandrashtama comes back about once a month, a little more often than that in practice. It happens to everyone, in short stretches spread through the year.
It begins and ends at the moment the Moon crosses into and out of the sign. That moment is the same everywhere on Earth, but the clock time depends on where you live. A Chandrashtama that begins late at night in Delhi begins in the afternoon in New York and in the evening in London; one that begins just after midnight in Delhi begins on the previous calendar day in both. So times printed in an Indian calendar will not match your local clock if you live abroad, and they often will not match your local date either.
Why the eighth
Counted from the Moon, the eighth house is traditionally the house of the hidden and the unexpected: delays, obstacles, matters outside your control. The Moon governs the mind and its moods. When the Moon passes through the eighth from its birth position, tradition says the mind is less settled than usual: more distracted, more easily unsettled, quicker to misjudge.
That is the whole classical reasoning. It describes a mood, not an event.
What it is traditionally avoided for
Since Chandrashtama is about a restless mind, what it advises against are the things that need a clear head and a fresh start:
- beginning something important, such as a new job, a business or a project
- signing agreements or making large commitments
- setting out on a journey that was planned specifically to be auspicious
- ceremonies chosen by muhurat, such as a griha pravesh or an engagement
- difficult conversations you can put off, or arguments you can walk away from
Because of this, people who set a muhurat for a family event also check that it does not fall in Chandrashtama for the main person involved. It is one of the routine checks on a date, not a special alarm.
What it is not
It is worth being clear about this, because Chandrashtama is often explained with far more fear than the tradition behind it.
- It is not a disaster day. The classical readings speak of worry and of plans going sideways, not of catastrophe. The advice that follows is modest: your judgement may be less steady, so it is sensible not to make big decisions then.
- It is not a day to stop living. Work you have already started carries on. You go to the office, keep appointments and look after your family. The caution is about starting things, not doing them, which is the same distinction that applies to Rahu Kaal.
- It is not rare or personal. Everyone with your Moon sign has the same Chandrashtama at the same moment, about once a month, for life.
- It is not the same as Ashtama Shani. That is Saturn in the eighth from your Moon sign, one of the two dhaiya phases, which lasts years and belongs to the same family of Saturn transits as Sade Sati. Chandrashtama is the Moon, and it is over in a couple of days.
The rest of the chart matters too, as it always does. A short lunar transit is a small thing on top of the dasha you are running and the larger transits around you. In practice, the traditional advice comes down to this: if a choice can wait two days, let it wait.
Different ways of listing it
North Indian calendars generally list Chandrashtama by sign. Many South Indian calendars, especially Tamil ones where chandrashtamam appears in the daily panchangam, list it against birth stars (nakshatras), grouping together the stars that fall in each Moon sign. It is the same Moon in the same sign either way; the lists are simply organised differently.
One detail trips people up. A few nakshatras, such as Krittika, Punarvasu and Chitra, are split across two signs, so a star-based list may name the same birth star on two different stretches, or specify which quarter (pada) it means. If your birth star is one of these, your Moon sign is the reliable thing to go by.
How to find yours
First, your Moon sign. If you do not know it, the Moon sign calculator works it out from your date, time and place of birth. The time matters: the Moon changes sign every couple of days, so someone born on a day the Moon changed sign could have either one.
Then, your dates. The weekly rashifal marks Chandrashtama days for each rashi alongside the week's better days and the planets changing sign, and the daily rashifal page for your rashi shows the date your next one begins. Both are worked out from the Moon's actual position rather than a fixed table. They are read for a morning in India, though, so if you live abroad, treat the days at either end of a stretch as approximate.
For a closer look at a particular day and place, the panchang shows the Moon's sign at sunrise and the nakshatra, with the time the nakshatra changes, for the city you choose.
Chandrashtama is a useful thing to know about and an easy one to plan around. At most it is a reason to wait a couple of days before a big decision, and it is not worth being frightened by.