For the scientists, coming to Senegal was a process of elimination. Most of the areas that offered the best viewing were in the middle of the Atlantic Ocean. The other options — in neighboring Mali, for example — were in areas patrolled by violent extremists.

The countryside of Senegal is peaceful, parts of it do not have electricity, and many rural areas are sparsely populated. That was a bonus for the scientists, who wanted a clear sky, free of light. Still, Senegal was a risky proposition. The area is on the cusp of the rainy season, and cloudy skies threatened to block the event, which occurred early Saturday and lasted less than a second.

Scientists are still evaluating data from the viewing, but the skies turned out to be clear and they are hopeful.

Senegal was an enthusiastic host. About two dozen Senegalese astronomers and scientists, including Ms. Sylla, accompanied the New Horizons team in the field and contributed to the viewing.

African countries have racked up their own space achievements. Moroccan astronomers have discovered comets, asteroids and planets outside our solar system. Ghana’s first satellite is now orbiting the earth. Students in Tunisia have organized public events to observe the sky, even though they do not have an observatory.

“Astronomy is virtually as popular in Africa as it is everywhere in the world,” said David Baratoux, the president of the African Initiative for Planetary Sciences and Space, who is based in France.

The biggest hindrance is money. The United States spends more on its space program than the value of Senegal’s entire economy. The 21 high-powered telescopes brought by the New Horizons team were nearly double the number of telescopes available in all of Senegal.