The explicit astronomical content of the great monument of Antiochus I of Commagene on the summit of Nemrud Dagh warrants the search for astronomical significance in the design of other monuments of this ancient Near Eastern kingdom of the first century BCE. The article advances the hypothesis that the nearby monument of Karakush, built by Antiochus’ son, Mithradates II, as a burial site for the royal women, was astronomically oriented, its three sets of peripheral columns being so positioned that during June Leo would be observed setting behind the lion columns after sunset, Aquila culminating over the eagle columns around midnight, and Taurus rising behind the bull columns before dawn. It is suggested, furthermore, that the astronomical occasion for the foundation of this second monument was a recurrence of significant planetary conjunctions in Leo. The ‘lion horoscope’ of Nemrud Dagh records the conjunctions of 62 BCE; the Karakush site may be related to the conjunctions of 27-26 BCE.