Do Mountains Suffer from the Moon Illusion? Jeff Nighbert Bureau of Land Management Portland, Oregon Jeff_Nighbert@or.blm.gov Abstract The "Moon Illusion" has been a topic of wonder and debate for many centuries. It is described in early Chinese and Greek writings. Most people see the "moon illusion" when the moon is next to the horizon, because it appears much larger than it does when it is high overhead in the sky. Though scientists concerned with this phenomena continue to theorize the causes, there is no denying that most people experience this illusion. But what does that mean for panoramists and 3d nature visualists? If the moon illusion is true, then it would follow that any prominatory, such as a singular mountain peak may suffer from the same exaggerated perceptions? If we "see" mountain peaks much larger than they really are, then should this exaggerated perception be carried forward into panoramic and virtual views of the landscape? This presentation will review popular "moon illusion" theories and then discuss how they would apply to visualization techniques and mapping applications in mountain cartography.