Marvana has no moon. Instead, the night sky is dominated by The Shattered Veil—a cosmic ring of glowing, multi-colored stardust and planetary debris left behind when the ocean evaporated.
Because the Great Salt Flats are completely featureless, navigation by landmarks is impossible.
Admiralty land-galleons and privateer gliders navigate the desert exactly like ancient mariners. They use brass quadrants and astrolabes to align their paths with the glowing clusters of the Shattered Veil. If a ship loses sight of the stars during a dust storm, they are effectively lost at sea.