Bad Astronomy: Misconceptions and Misuses Revealed, from ...

APPALLED AT APOLLO 171
The shadows cast by the astronauts, rocks, and other surface
features appear to be nonparallel, but this is just an effect of
perspective, similar to the apparent converging of railroad tracks
on the horizon.
curved. That’s all there is to it. Again, no fakery, just simple optics
that everyone has seen at some point in his or her life.
However, there are also some images that are not visor reflections,
but still seem to have shadows pointing in different directions.
Again, if the Sun is the only source of light, shadows should
be linear and parallel. Clearly, sometimes they are not parallel. To
the conspiracy theorists, of course, this is more evidence that the
images are fake.
Have you ever stood on a set of railroad tracks and seen how
they appear to converge far away, near the horizon? This is an
effect of perspective, of course. The railroad tracks are parallel
(they wouldn’t be much use if they weren’t), but our eyes and
brain interpret them as converging.