Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 7 · Samskara Muhurtas
संस्कारमुहूर्ताः
शाखाधिपतिवारश्च शाखाधिपबलं शिशोः ।शाखाधिपतिलग्नं च दुर्लभं त्रितयं व्रते ॥ ३६७ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 367.
Take the shakhesha's (lord of the person's Veda branch) weekday. Take the shakhesha's strength for the boy. Take a lagna (rising sign) of the shakhesha. These three together are hard to get for the vrata (vow rite).
Simple meaning: The branch lord's day, his strength and his rising sign are rarely found together.
श्रवणादिनि नक्षत्रे कर्कांशस्थे निशाकरे ।
Moon in Shravana or Punarvasu, in a Cancer navamsha, brings learning, wealth and grain.
शुभलग्ने शुभांशे च नैधने शुद्धिसंयुते ।
Choose a good rising sign and navamsha, a clean 8th house, and help from good planets.
इष्टैर्जीवार्कचंद्राद्यैः पंचभिर्बलिभिर्ग्रहै ।
Five strong planets are best. Four strong, well-placed ones also work.