# The Great Calculation According to the Indians, of Maximus Planudes - On the Circle of the Zodiac

Author(s):
Peter G. Brown

Let us now make some comments about the zodiac, degrees, first parts, and secondary parts.36 Note then that the sun passes through the 12 signs of the Zodiac as it passes through its cycle. Each of these is divided into 30 degrees and each degree is divided into 60 primary parts and each primary part into 60 secondary parts, and each secondary part into 60 tertiary parts and so on forever. Astronomers ignore all the rest and only concern themselves with 4 quantities, that is, the signs of the Zodiac, degrees, primary parts, which they simply call 'minutes' and 'seconds' leaving out the mention of 'parts' from the 'seconds' and 'primary' from the 'minutes'.

ON ADDITION:

Whenever you wish to perform an addition, you do it as follows: Write down zodiac, degrees, minutes and seconds, whatever you find in the ****37 of Astronomy, but if not, then whatever you like. Below write the number of the zodiac, the number of degrees in their columns and likewise the number of minutes and seconds. For example, the following diagram makes clear what we are saying.

$\begin{array}{|cccc|}\hline {\rm{Zodiac}} & {\rm{Degrees}} & {\rm{Minutes}} & {\rm{Seconds}} \\ \hline 0 & 22 & 57 & 35 \\ \hline 3 & 18 & 44 & 52 \\ 4 & 23 & 54 & 49 \\ 2 & 25 & 32 & 25 \\ 1 & 14 & 45 & 29 \\ \hline 2 & 22 & 12 & 2 \\ \hline \end{array}$

So beginning from the last38 entry, 9 and 5 make 14 and 9 is 23and 2 is 25. Write the 5 above and hold the 2 which we will add to the next column. 2 and 2 is 4 and 2 is 6 and 4 is 10 and 5 is 15. See how many times we need to subtract 6 from 15 and we see it is 2 remainder 3. Write the 3 above the second row, above the 5 and the 2 under the 5 in the minutes column. Say 2 and 5 is 7 and 2 is 9 and 4 is 13 and 4 is 17. Write the 7 above the four and carry one. Again we say 1 and 4 is 5, 5 and 3 is 8 and 5 is 13and 4 is 17. Check again how many times we can take away 6. It is 2 remainder 5. Write the 5 and carry the 2. Take this with the degrees and say 2 and 4 is 6, 6 and 5 is 11 and 3 is 14 and 8 is 22. Write the 2 and carry the 2. Say 2 and 1 is 3 and 2 is 5 and 2 is 7 and 1 is 8. See how many times you can take 3 from 8 and it goes 2 remainder 2. Write the 2 and carry 2, which is twice thirty. Again say 2 and 1 is 3 and 2 is 5 and 4 is 9 and 3 is 12. Take away twelve and zero is left.39 The answer is 22 degrees, 57 minutes and 35 seconds and the sign of Aries40.