Rahu and Ketu are always retrograde. Retrograde planet is just a phenomenon where the planet is perceived to be moving backward. Many Astrologer debate on it as how to judge retrograde planets. But,As I follow, System Approach Astrology, where it is said that Retrograde planets shall also be considered in the same way as other planets, only transit effects could be prolonged to due to planet’s retrograde nature. Stronger the Rahu, better the Result. Ofcourse, sign placement and any other benefic aspect or negative affliction shall be considered.