In most real mirages, each ray is confined to a single plane giving collinear images. A contiguity principle suffices for the triple image form. Inversion of any image can be associated with contact of the corresponding ray with a caustic.
© 1990 Optical Society of America
Original Manuscript: October 2, 1989
Published: August 1, 1990
Richard White, "Mirage: multiple images," Appl. Opt. 29, 3204-3206 (1990)