The aspect ratio listed for The Odyssey on IMAX 70 mm film prints is 1.43:1.
An aspect ratio compares an image’s width with its height. The 1.43:1 format is much taller than standard widescreen cinema, allowing IMAX presentations to show substantially more vertical image. For The Odyssey, the ratio is associated with the expanded presentation available at specially equipped IMAX 70 mm locations.
The format comes from IMAX’s 15/70 system: each frame uses 70 mm film running horizontally through the camera and projector, with 15 perforations per frame. That produces a physically large image and the characteristic tall frame. Not every cinema can display the full image, so other releases may use wider presentations or crop the frame to fit the auditorium.
The main confusion is between the film gauge and the aspect ratio. “70 mm” describes the film format, while 1.43:1 describes the shape of the projected image. Standard 5-perforation 70 mm is commonly associated with a much wider 2.20:1 ratio; IMAX 70 mm is the taller 1.43:1 format.