Bonilla observation, Zacatecas
Astronomer José Bonilla saw and photographed hundreds of dark objects crossing the Sun, often cited as the first UFO photograph.
1883 CE · 22.77, -102.58 · status: explained
The account
On 12 August 1883, while watching sunspots at Zacatecas Observatory, José Árbol y Bonilla counted more than 300 dark objects passing in front of the solar disc and took wet-plate photographs.
The sceptical view
Proposed explanations have included high-flying birds or insects; a 2011 study argued the objects were fragments of a comet passing close to Earth.
The researched reading
A careful astronomer genuinely saw hundreds of dark specks cross the Sun. The simplest reading is that they were birds or insects near the instrument, out of focus; the comet hypothesis is ingenious but has little support.
| Explanation | Weight | Why |
|---|---|---|
| Something known, misidentified | 77% | Objects close to a telescope focused on the Sun (birds on migration, insects, airborne seeds) appear as dark, fuzzy shapes crossing the disc; August is a migration month, and the surviving photograph shows an out-of-focus blob consistent with a near object. |
| A known natural phenomenon | 10% | A 2011 paper proposed a fragmented comet passing very close to Earth, but critics note the absence of any matching comet, meteor storm or night-time effects, which makes it unlikely. |
| Genuinely anomalous | 5% | A trained observer and a photograph make the sighting real, but nothing in it requires an unknown cause. |
| A poorly understood natural phenomenon | 3% | An unusual swarm of meteoroids or atmospheric debris that fits no standard category remains a small possibility. |
| A hoax or fabrication | 3% | Bonilla published his report openly in L’Astronomie and had no clear motive; fabrication is unlikely. |
| Perception, memory or mind | 2% | He counted carefully over two days; misperception of the basic event is unlikely, though the interpretation of distance was his. |
| Secret human technology | 0% | No flying technology existed in 1883. |
Official position: No official investigation; often cited as the first UFO photograph, and explained by sceptics as birds or insects near the telescope.