Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 8 · Marriage
विवाहः
अप्रबुद्धो हृषीकेशो यावत्तावन्न मंगलम् ।उत्सवे वासुदेवस्य दिवसे नान्यमंगलम् ॥ ४२० ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 420.
As long as Hrishikesha (Vishnu) is not awake, there is no good rite. On the day of Vasudeva's (Vishnu's) festival, no other good rite is done.
Simple meaning: No marriage while Vishnu sleeps, and none on the day of his festival.
न जन्ममासे जन्मर्क्षे न जन्मदिवसेऽपि च ।
A first child should not marry in the birth month, birth star or on the birthday.
नैवोद्वाहो ज्येष्ठपुत्रीपुत्रयोश्च परस्परम् ।
Two eldest children should not marry in Jyeshtha. If only one is eldest, Jyeshtha is fine.
उत्पातग्रहणादूर्द्धं सप्ताहमखिलग्रहे ।
Avoid seven days after a total eclipse and three after a partial one.