The Dogons also claimed that Jupiter had 4 moons. They were only off
by about 60-something or so.

They also claimed that Saturn had rings, which is correct - but apparently
their space-travelling "gods" somehow missed the rings around the other three
gas giants, or maybe they felt the primitive humans were not ready to handle
such news. "More than one planet with rings - gasp! There goes our way of
life!"

More info here, especially if you scroll down to the section titled "Hunt for
Sirius C and Substellar Companions":

http://www.solstation.com/stars/sirius2.htm

As for specific skepticism on the Dogon mythology, see here:

http://www.astrosociety.org/education/resources/pseudobibprint.html

6. The Dogon Tribe and Sirius B

Several popular authors have touted the story of an African tribe that somehow acquired knowledge of the dim white dwarf star around Sirius (which is visible only with the aid of larger telescopes.) Some see this as evidence of extraterrestrial visitors, but the real explanation probably involves the European visitors who were gathering information about the tribe and had read about the discovery of Sirius B before they left.

Brecher, K. "Sirius Enigmas" in Brecher, Kenneth & Feirtag, M., eds. Astronomy of the Ancients. 1979, MIT Press.

Krupp, E. "Observatories of the Gods and Other Astronomical Fantasies" in Krupp, E.C., ed. In Search of Ancient Astronomies. 1977, Doubleday. Debunks von Daniken and Velikovsky's ideas, as well as the Sirius myth.

Ortiz de Montellano, B. "The Dogon People Revisited" in Skeptical Inquirer, Nov/Dec. 1996, p. 39. Excellent up-to-date review.

Ridpath, I. "Investigating the Sirius Mystery" in Skeptical Inquirer, Fall 1978, p. 56. (On line at: http://www.csicop.org/si/7809/sirius.html)

Sagan, Carl "White Dwarfs and Little Green Men" in Broca's Brain. 1979, Random House.

Web Sites:

Sirius Matters: http://chandra.harvard.edu/chronicle/0400/sirius_part2.html The Chandra Observatory site has a short, skeptical introduction to this issue.

Sirius Mystery: http://www.debunker.com/texts/dogon.html Space journalist James Oberg takes a skeptical look in an excerpt from a 1982 book.

The Dogon Revisited: http://www.ramtops.demon.co.uk/dogon.html Text of article by Bernard R. Ortiz de Montellano.