Ketu

Ketu is the Moon's descending node, the opposite point to Rahu. The Brihat Jataka gives the name Sikhi for it in the same stanza that names Rahu. The quoted line, a single verse from the Brihat Parashara Hora Shastra as typed in Sanskrit on Wikisource, from an edition no one has named, ends the order of the nine grahas with Ketu. In the calculator Ketu is always 180 degrees from the mean Rahu.

The Brihat Jataka as translated by Iyer gives Ketu the same blank as Rahu: no sign, no exaltation or fall, no friendship row and no special aspect in the passages read here. The seven bodies fill those tables. Chapter 46 of the typed Sanskrit text goes further and drops Ketu from the lords of its Ashtottari dasha, one of the other timetables it describes beside Vimshottari.

Ketu appears in full in the Vimshottari timetable, where the sequence begins with it when counted from Ashvini. Its period is 7 years, and it belongs to Ashvini, Magha and Mula. Iyer's table writes the order from the Sun instead: Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu, Venus. Both orders cycle through the same nine lords.