Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
बहुधारविजस्त्वेतद्वक्रगः फलमीदृशम् ।करोत्येव समः साम्यं शीघ्रगेषूत्क्रमात्फलम् ॥ ७८ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 78.
Saturn moving backward gives these results many times over. At even speed he gives them as they are. When fast, he gives them reversed.
Simple meaning: Retrograde Saturn makes these results stronger. Fast Saturn turns them the other way.
विष्णुचक्रोत्कृत्तशिराः पङ्गुः पीयूषपानतः ।
Vishnu's discus severed Rahu's head, but nectar made him immortal and he became a planet.
वरणधातुरर्केन्दू तुदते सर्वपर्वणि ।
Rahu troubles the Sun and Moon at new and full moons, but at times is too far to eclipse them.
षण्मासवृद्ध्या ग्रहणं शोधयेद्रविचंद्रयोः ।
Eclipses of the Sun and Moon are found six months apart. Seven gods rule the eclipse seasons in turn.