Abstract

Inferior mirages above hot roads and in the desert are well known. Less familiar are mirages above wet sand banks and mud-flats(watt). Off North Friesland in Germany there is a unique region of mud-flats with about 10 small flat islands with one or a few houses(warft), called Halligen. The distance between these Halligen is 5-10 km. In summer at low tide good conditions often exsist for the appearance of mirages. Typically the mirages are simple inferior mirages. The mirages of Halligen are striking, they look like airships at the horizon [1]. But sometimes the mirages are more complex and cannot easily be explained.

© 1997 Optical Society of America