So, in the 1930's a team of French anthropologists, Marcel Griaule and Germaine Dieterlen, did a detailed study of the Dogon tribe. They were considered a very important group to study as they were some of the "least contacted" tribes in Africa, part of the last remaining regions to be conquered by Europeans only very recently. As such they were considered a very "virgin" culture, uncontaminated by outside influence.
One of the things they noted is that they had a very detailed understanding of astronomy... unusually so. They were somehow aware that Saturn had rings. This discovery was unknown to Europeans until the 1600's by aid of the telescope.
But most impressively, they were aware that Sirius was actually a double star system. In fact, they had many rituals related to Sirius, and they believed that they came to Earth from Sirius.
That Sirius was a double star system wasn't discovered until the mid 1800's. They knew that the "invisible" companion star took ~50 years to orbit. They knew that the companion star was unusually heavy, a mystery that wasn't fully solved until the 1930's. They even seemed to know about the strange motions of Sirius, caused by how the double star system moves in an elliptical orbit (something not well understood until the works of Kepler and Newton 1600~1700), and something undetectable without incredibly accurate telescopes.
This, obviously, caused a bit of a crisis. How did they know so much?
Their primary god, Nommo, is a hermaphroditic, green, tentacle monster, so obviously they had contact with aliens. Or obviously the Dogon were secretly a very advanced people, who hid their tech. Wakanda? Or both Aliens and Wakanda? But the funny truth is............
The tribe wasn't actually so uncontaminated as initially thought.
In 1893, several astronomers traveled to the region to observe a solar eclipse, and had extensive contact with some of the Dogon people. During this time, they may have told them some astronomy trivia.
Sirius may have already been important to them, it's an incredibly bright star (the brightest after the sun), so they incorporated what they were told into their religion, including adding a once every 60 year, 7 year long celebration called sigui, for the cycle of Sirius that seems to coincide roughly with the first contact by the astronomers. The next one is in 2032, so if you want to partake, now's your chance!
People have, obviously, gone back to talk to these people but what's strange is that most of them don't seem to have the advanced astronomical knowledge that Marcel Griaule and Germaine Dieterlen claimed. They didn't even know which star was Sirius (identifying Jupiter, Venus, Sirius, and even suggesting "sigui" is an unseen "invisible star".
So what might have also happened is that Marcel Griaule and Germaine Dieterlen are actually the source of the contamination. There's almost no evidence that the Dogon had any deep understanding of astronomy prior to contact with the anthropologists, let alone astronomers from the 1890's, and afterwards too.
In asking about sigui rituals, the Dogon might have bullshitted them into thinking the Dogon were talking about Sirius, and that the "invisible star" was obviously Sirius B.
Or they had a brief contact with some astronomers in 1890 which kicked off a cargo cult, that was further contaminated by anthropologists.
Meanwhile, there are people who honestly believe that the Dogon are actually a secretly advanced race of interstellar travelers.