On a level square surface, at a distance of ten digits, the East-West line is established rishta? The text here is slightly obscured, but refers to the placement of the gnomon to observe the desired shadow. This means the desired shadow is produced.

In the center, a line should be drawn using "fish" marks original: "timinā"; a geometric technique where two intersecting arcs create a fish-shape to find a perfect perpendicular line running North to South. 3. Between the North and South directions, another line should be drawn from the "fish" marks running East to West.

From the center of these directions, the intermediate directions should likewise be established. 4. One should construct a square on the outside using the lines extending from the center. With arms of three digits likewise established by the desired shadow, 5. the line resting between East and West is called the prime vertical sama-maṇḍalam. 6.

This circle is also known as the equinoctial circle viṣuvan-maṇḍalam. 6. The East-West line should be established such that it follows the path of the equinox. The shadow of the gnomon at the equinox is here called the mean shadow. 7.

The square root of the sum of the squares of the gnomon and its shadow is the hypotenuse. From the square root of the gnomon's square, the shadow and gnomon are determined inversely. 8.

The word Kriti meaning 'square' or 'action' refers to twenty. It is multiplied by thirty, meaning six hundred. == 6

The Origin of the Precession of the Equinoxes

In an Age yuga, the circle of asterisms the stars/zodiac moves forward six hundred times. Multiply the result by 600 and divide by the number of days in an Age to find the current position. 9. From that, find the portion of the three-tens 30 degrees. These are known as the degrees of precession ayanāṃśa. By applying this correction to the planets, the declination, the shadow, and the half-day variations 10. become clear and reach agreement with observation. At the two solstices and the two equinoxes, the circle has moved forward; if the shadow is less than that produced by calculation, 11. the difference in degrees is added; if the shadow is greater, it is subtracted. Thus, at the equinox, if the shadow in one's own country is not straight i.e., not perfectly aligned with the expected latitude 12. on the North-South line, that is the equinoctial shadow viṣuvat-prabhā. The radius-sine multiplied by the shadow and divided by the equinoctial hypotenuse 13. gives the sines of the latitude and co-latitude. From the arc of these two, hoda? the North-South mean position is found.