The Wonder of Calculation (Karana Kutuhala)

The "Rāma-correction" Rāmabīja: a set of longitudinal corrections attributed to the astronomer Rāmacandra is written on that leaf, but it was neglected because the difference was so small. However, it is recorded here as stated by modern calculators:

"Add two minutes to the Sun; subtract fifteen original: 'tithi-kalā,' where 'tithi' represents the number 15 minutes from the Moon.
For Mars, add eighty minutes; for Mercury, add seven hundred.
For Jupiter, subtract one hundred and ninety original: 'khanandaika' — kha (0), nanda (9), eka (1); for Venus, subtract two hundred and seventy original: 'khabhāni' — kha (0), bha (27).
For Saturn, add ninety; and thirty for the lunar apogee and node.
When this is done, the planets are surely corrected for the present time.
They will always be suitable for sighting through the tube-instrument nalikā-yantra: a sighting tube used for astronomical observation during eclipses and other phenomena."

Knowing that even these had some discrepancy, those corrections made by the teacher Rāmacandra are also written here:

"Two minutes should be added to the Sun, and thirty-four original: 'kṛtarāma' — kṛta (4), rāma (3) minutes subtracted from the Moon. For Mars, add four hundred and twenty original: 'adhrivishva' — adri (7)? No, the text says 'adhrivishva' which usually implies 137, but the table clarifies the intended values minutes; for Mercury's fast motion, add six hundred and eighty. For Jupiter, subtract one hundred and ninety. For Venus's fast motion, subtract three hundred. For Saturn, add four hundred and eighty. For the lunar apogee, add thirty, and for the node, subtract thirty."

Both of these are to be understood through instruments. The "equation of the lunar day" bhāṃshaphala applies only to the Moon. The "equation of time" udayāntara applies only to the Sun and Moon. The "ascensional difference" charakarma applies to all. As stated in the Lamp of Calculation original: 'Karaṇapradīpa,' a 14th-century astronomical text:

"Some say the correction for geographical longitude deshāntara, the annual secular correction ābdaka, and the correction for the equation of the center bhujāntara constitute the 'Rāma' correction. The authority here is tradition; by these, the planets become corrected and suitable for calculation."

Some operations are applied to the mean positions, and some to the true positions. The procedure for the "ascensional difference" charadala is performed by the wise after the calculation of the true positions. Here, the corrections for longitude, the annual secular change, and the Rāma-correction should be applied to the mean positions; the correction for the lunar day applies to the mean Moon only. Since the author of this treatise mentioned the equation of time and ascensional difference without specifying their refinement, it should be inferred that they are applied to the true positions. What more need be said? Now, to the matter at hand: through the operation starting with 'the years by the elephants and horses,' the longitude correction and the Rāma-correction are applied to the planets. The mean positions at sunrise are to be known from the instrument. || 16 ||

Thus ends the first chapter, on the calculation of mean planetary positions, in the commentary Moonlight for the Lily of Astronomers original: 'Gaṇakakumudakaumudī' composed by Sumatiharṣa on the Karaṇakutūhala. || 1 ||