Hayanaratna · by Balabhadra
Chapter 1 · Planets, Signs, Year Entry
ग्रहराशिस्वरूपवर्षप्रवेशाद्यानयनाधिकारः
त्रिंशन्निघ्नमशुद्धाप्तभागाद्यं मेषपूर्वकैः ॥अशुद्धात्प्राग्रहैर्युक्तं लग्नं स्याद्व्ययनांशकम् १
Multiply the remainder by 30. Divide by the rising time of the sign that could not be taken away. This gives degrees and so on. Add it to the signs, counted from Aries, before that sign. Then remove the ayanamsha (the zodiac shift). This is the lagna (rising sign).
Simple meaning: Rising sign degrees: remainder x 30, divided by the rising time of the next sign. Add to the signs passed, then remove the zodiac shift.
भोग्याल्पकालात्स्वत्रिघ्नात्स्वोदयाप्तलवादियुक् ॥
Rising sign when the wanted time is shorter than the Sun's remaining time: add a small part to the Sun itself. At night, start from the Sun plus six…
अत्र जन्मदेशीयमेषादिलग्नमानैर्लग्नस्पष्टीकरणं कर्तव्यं न त्वन्यदेशोदयैरिति ॥
Rising times: use those of the birth place, not another place.
अथ धनर्णं लग्नानयने विशेषः ॥
Rising sign by plus and minus: from sunrise or sunset count forward, before them count back. Both ways give the same rising sign.