Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
अग्निप्रदस्तेयचरवनसर्पविनाशकृत् ।विशाखामित्रयोर्याम्यपार्श्वगः पापगः शशी ॥ २१ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 21.
... may harm fire-setters, thieves, forests and snakes. The Moon on the south side of Vishakha and Anuradha is bad.
Simple meaning: A Moon south of these stars may harm thieves, forests and snakes. South of Vishakha and Anuradha it is bad.
मध्यमः पितृदैवत्ये द्विदेवे सौम्यगः शशी ।
A Moon north of Magha and Vishakha is middling. Joining the stars from Revati early is good.
मध्यगोद्वारदक्षाणि अतीत्य नववासवात् ।
The Moon meets some stars in the middle, others after passing. Six stars count as half-stars.
ध्रुवादितिद्विदैवाः स्युरध्यर्द्धाश्चापराः समाः ।
Some stars count as one and a half and others as equal. A raised south horn is bad.