Well have you asked, O brahmin, with a mind intent on the welfare of the world; out of affection for you I shall speak of the results for those whose birth is unknown.
Verse 5 — Unknown Measures Known from Prashna Lagna
वर्षायनर्तुमासार्धतिथिनक्षत्रभादिषु ।
यदज्ञातं च तन्मानं ज्ञायते प्रश्नलग्नतः ॥ ४॥
varṣāyana-ṛtu-māsārdha-tithi-nakṣatra-bhādiṣu | yadajñātaṁ ca tanmānaṁ jñāyate praśna-lagnataḥ ||
Whatever is unknown among the year, ayana (solstitial half), ritu (season), month, fortnight, tithi, nakshatra and their parts, that measure is known from the prashna (horary) ascendant.
One should declare the birth sign as that in whose dwadashamsha Jupiter stands in the prashna chart; the ayana is northerly (saumya) when Jupiter occupies the first half of the lagna sign and southerly (yamya) when in the second half.
The ritu (season) is determined by the lords of the signs connected with the lagna, beginning with the Moon; Saturn, Venus, Mars, the Moon, Mercury and Jupiter denote the seasons, while summer belongs to the Sun.