Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 7 · Samskara Muhurtas
संस्कारमुहूर्ताः
ईक्षन्नैवात्रैकविंशमहादोषविवर्जिते ।राशयः सकलाः श्रेष्ठाः शुभग्रहयुतेक्षिताः ॥ ३७२ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 372.
The time here is free of the twenty-one great faults. All signs are best when good planets join them or look at them. (Our text is unclear here: the opening word 'ikshan'.)
Simple meaning: Choose a time free of the twenty-one great faults. Any sign is good with good planets joining or looking.
शुभनवांशकगता ग्राह्यास्ते शुभराशयः ।
Take signs in a good navamsha. Never take a Cancer navamsha, even with good planets looking.
तस्माद्गोमिथुनांशाश्च तुलाकन्यांशकाः शुभाः ।
Taurus, Gemini, Libra and Virgo navamshas are good for the thread ceremony.
त्रिषडायगतैः पापैः षडष्टांत्यविवर्जितैः ।
Bad planets in the 3rd, 6th or 11th. Good planets away from 6, 8, 12. Moon away from 6, 8, 12, 1.