José Bonilla solar-transit photographs

Record summary

What happened Astronomer José Bonilla photographed numerous dark objects crossing the Sun while observing sunspots. He published drawings and photographs in L’Astronomie in 1886. Later proposals range from high-flying birds or insects near the telescope to fragments of a comet passing relatively close to Earth; the latter requires speculative distances not measured at the time. Evidence Contemporary telescopic photographs, Bonilla’s observing notes and later publication survive. Explanations considered Birds, insects, windborne debris or an unrecognised instrumental/optical effect are conventional possibilities; comet fragments are a later hypothesis. What remains uncertain A single observatory supplied no parallax, so distance, size and speed cannot be recovered from the images alone. Primary source José Bonilla solar-transit photographs — Wikipedia