Count the signs the degree has completed from Mesha and multiply by 9. Add which navamsa of its sign the degree is in (1 to 9, each 3°20′ wide). Divide by 12 and keep the remainder. Count that many signs from Mesha: 1 is Mesha, 2 is Vrishabha, and a remainder of 0 means Meena. That sign is the navamsa.
☕ Why a sum works
The navamsas of the twelve signs follow one another without a break. Mesha's first navamsa is Mesha, its second Vrishabha, and so on; Vrishabha's first navamsa picks up where Mesha's last one stopped. So the 108 navamsas of the zodiac run through the twelve signs nine times over, in order.
That means you only need to know how far along the zodiac a degree is, counted in navamsas. Each complete sign holds 9 of them; add the navamsa the degree has reached inside its own sign. Dividing that count by 12 strips off the full rounds, and the remainder is the sign. The shortcut comes from a translator's note on the navamsa stanza (Brihat Jataka, ch. I, v. 6), restated here in our own words.
The same 108 lines up with the stars. Each sign holds two and a quarter stars (Brihat Jataka, ch. I, v. 4), so each star quarter, a pada, is 3°20′: exactly one navamsa. The worked examples below show the sum on two degrees; the result is the sign Nava's navamsa chart puts there.
Two worked sums
- Kanya (Virgo) 14°: 5 signs are complete, so 5 × 9 = 45; the degree falls in navamsa 5 of the sign; 45 + 5 = 50; divided by 12 that leaves 2. The navamsa is Vrishabha (Taurus).
- Kumbha (Aquarius) 17°20′: 10 signs are complete, so 10 × 9 = 90; the degree falls in navamsa 6 of the sign; 90 + 6 = 96; divided by 12 that leaves 0 (a remainder of 0 means Meena). The navamsa is Meena (Pisces).
- Mix-up: a remainder of 0 is an error. It means the count landed on the twelfth sign, Meena.
- Mix-up: the navamsa place is the degree divided by 3. The parts are 3°20′ wide, not 3°: 28° is in the 9th part (26°40′ to 30°), while dividing by 3 would point past the ninth.
- Mix-up: the sum needs a different rule for fixed and dual signs. It does not; the rule of starting from the 9th or 5th sign is already built into the running count.
Frequently asked questions
Does this give the same answer as the movable, fixed and dual rule?
Yes, for every one of the 108 navamsas. The book's rule says where each sign's count starts; the sum reaches the same sign by counting from Mesha all the way.
What if the degree sits exactly on a boundary such as 3°20′?
A boundary belongs to the part that begins there. 3°20′ is the start of the 2nd navamsa of its sign.
Do I need this if Nava draws the chart?
No. It is a check you can do on paper, and it shows why the navamsa follows from the degree alone.
Deep dive: the long way, and the 108
The book's own rule, and what this builds on.
🔢 The long way
The book's rule counts each sign's nine parts from a different start: from the sign itself if it is movable, from its 9th if it is fixed, from its 5th if it is dual. It is on Brihat Jataka’s five vargas. The 108 star quarters that line up with the navamsas are on the 108 padas.
🧭 What this builds on
The order of the twelve signs, and which are movable, fixed and dual, is on the twelve rashis.