The
Sun has just set... in the opposite side of the sky.
Pictured
here are
anticrepuscular rays apparently converging in the east in this image of the
limestone plateau in the heart of the
Hyblaean Mountains of southeastern
Sicily, in Italy.
How were these anticrepuscular rays formed, if the Sun
wasn't there?
After the Sun set (in the west, as usual) its light still illuminated a
cloud higher up in the sky.
Partially blocked by the cloud, the sunlight produced
patterns of light and shadow, crossing the sky in parallel lines.
Perspective makes it look like they converge in the east, in the same way that
train tracks appear to meet in the distance.
This effect can also h/day/pen at
sunrise, only the directions are exchanged.
In
rare cases, both
crepuscular and anticrepuscular rays can be seen
at the same time.