Altocumulus (Ac)

A cloud layer of altocumulus undulatus is displayed here which is characterized by its wave-like substructures. These clouds existed over some hours before disappearing in the late afternoon.

AcUnd1.jpg and AcUnd2.jpg: S. Borrmann, Ingelheim, Germany, July 2002

Optical_Illusion1.jpg and Optical_Illusion2.jpg: Rob Gonsalves, "The sun raises its sails" (Die Sonne setzt die Segel), Acryl on Canvas, 101,5 cm x 51 cm, 2001, from Seckel, Al., Große Meister der optischen Illusionen, Band 1, tosa Verlagsgesellschaft, 2005.