A statistical analysis of the orientation of Nabatean sacred monuments demonstrates that astronomical orientations were often part of an elaborated plan and possibly a trace of the astral nature of the Nabataean religion. Petra and other monuments in the ancient Nabataean kingdom have proven to be marvellous laboratories for the interaction between landscape features and astronomical events, showing impressive hierophanies on particular monuments related to cultic times and worships. Among other findings, the famous Ad Deir has shown a fascinating ensemble of light and shadow effects, perhaps connected with the bulk of Nabataean mythology, while from the impressive Urn Tomb, a series of suggestive solstitial and equinoctial alignments emanate which might have lately helped its selection as the cathedral of the city. This paper demonstrates that the sky was a substantial element in Nabataean religion and reveals new evidence for cultic worship centred on the celestial sphere.