I will warn you that those out-of-this-world images of Petra by Night with the Treasury and the Stars above are not taken by ordinary travellers with a camera. They are taken by professional photographers who not only know a great angle when they see one, but also are well versed in exposure, depth of field and have lots of practice exposing for stars. They probably have those camera's mounted on a tripod that costs more than your camera!  With the limited lighting, your cell phone will probably get a shaky image of the candles and the Treasury. Do not expect much more.