Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 7 · Samskara Muhurtas
संस्कारमुहूर्ताः
धृम्रगर्द्दभयोर्नैव व्रणं श्रेयोंत्यभागगम् ।अथोत्तरायणे शुक्रजीवयोर्दृश्यमानयोः ॥ ३९१ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 391.
With Dhuma (smoke) and Gardabha (ass), there is no flaw at all. A flaw in the end part is the better one. Next: in the uttarayana (the Sun's northward course), when Venus and Jupiter can be seen...
Simple meaning: Dhuma and the ass mean no flaw in the blade. Next come the rules for the return-home rite.
द्विजातीनां गुरोर्गेहान्निवृत्तानां यतात्मनाम् ।
For men back from the teacher's house, good stars are Chitra, the Uttaras, Punarvasu, Pushya, Revati, Shravana, Anuradha and Rohini.
भेष्वर्केंदुज्ञेज्यशुक्रवारलग्नांशकेषु च ।
Use those stars and the Sun, Moon, Mercury, Jupiter or Venus days. Avoid the 1st, 8th, empty days and new moon.
हित्वान्यदिवसे कार्यं समावर्तनमुंडनम् ।
Do the return-home rite and head-shaving on another day. The householder stage is the best of all.