The Bonilla Observation
In 1883, a Mexican astronomer watching the Sun counted more than 400 dark objects crossing its face, and photographed them.
What was reported
On 12 August 1883, José Bonilla, director of the observatory in Zacatecas, was observing sunspots when he saw a stream of dark objects crossing in front of the Sun. Over two days he counted 447 of them, and took photographs, some of the earliest of their kind.
He published his observations in 1886 in the French journal L'Astronomie. No other observatory reported seeing them.
Explanations offered
The journal's editors suggested the objects were birds, insects or dust passing close to the telescope, which would explain why no one else saw them. In 2011, researchers at Mexico's national university argued they might have been fragments of a comet passing very close to Earth. Neither explanation is agreed.
- When
- 12–13 August 1883
- Where
- Zacatecas Observatory, Zacatecas, Mexico
- Witnesses
- Astronomer José Bonilla
- Status
- Disputed
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.