Cakra-yantra

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Cakra-yantra, or circle instrument was an instrument used by Vedic astronomers. [1]

It was one of Lalla's 12 instruments of astronomy.[2]

Lalla described it as a 360° graduated circular board which had a central upright needle. The whole thing was tilted at a certain angle. It indicated nāḍis elapsed since sunrise, or nāḍis to-elapse before sunset. Subbarayappa and Sarma note problems with the calculation method described by Lalla. They also describe a criticism made by Brahmagupta on the matter of calculating nāḍis. [1]

Half of a Cakra is a Dhanur-yantra, a half-circle. Modifications can be made resulting in instruments like the Kapāla-yantra and Pīṭha-yantra. [3]

References

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