Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
रोहिणी मंदवारे च सिद्धियोगाह्वया अमी ।आदित्यभौमयोर्नंदा भद्रा शुक्रशशांकयोः ॥ २४३ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 243.
Rohini on Saturday. These are named Siddhi yoga (good or bad day mix). Nanda is on Sunday and Tuesday. Bhadra (tithis 2, 7 and 12) is on Friday and Monday.
Simple meaning: Rohini on Saturday completes the Siddhi days. Nanda and Bhadra fall on certain weekdays.
जयासौम्ये गुरौ रिक्ता शनौ पूर्णेति नो शुभाः ।
Some tithi and weekday pairs are not good. Then a second set of pairs starts.
रिक्ता मंदे गुरोर्वारे पूर्णा सिद्धाह्वया अमी ।
These pairs are called Siddha. Then pairs of weekday and tithi begin: Monday on the 11th, Sunday on the 12th.
षष्ठी गुरौ तृतीया ज्ञेऽष्टमी शुक्रे शनैश्चरे ।
These weekday and tithi pairs are called burnt days.