Rainbow Wheel Over São Paulo, Brazil
March 01, 2018
Shown above is a rainbow wheel observed over São Paulo, Brazil, in the late afternoon of January 15, 2018. Anticrepuscular rays, here passing through both the primary rainbow and the secondary bow, serve as the spokes of the wheel. These rays formed when clouds (likely cumulonimbus clouds) on the opposite horizon from where this rainbow was viewed blocked some sunlight, the darkened lanes while allowing some light to filter through cloud gaps and project across the entire sky. Perspective makes it appear that the rays are converging. Note that both the primary and secondary bows, as well as the anticrepuscular rays, have the antisolar point as their focus.
Photo Details: Camera: Canon PowerShot SX40 HS; Exposure Time: 0.0080s (1/125); Aperture: ƒ/4.0; ISO equivalent: 100; Focal Length: 4.9mm; Software: Picasa.