Edmond Modeste Lescarbault claims sighting of the planet Vulcan

Background. Urbain Le Verrier had confirmed unexplained peculiarities in Mercury's orbit by 1859, predicting they resulted from the gravitational influence of an unknown nearby planet. This hypothesis gained credibility due to Le Verrier's previous success in predicting Neptune. The name 'Vulcan' was proposed for this hypothetical planet, drawing from Roman mythology.

The Claimed Observation. Edmond Modeste Lescarbault, a French physician and amateur astronomer, began systematic observations of the Sun's disk in 1858 using a 3.75-inch refractor. On March 26, 1859, he reported seeing a small black dot on the face of the Sun, which he interpreted as a transit of an unknown planet.

Le Verrier's Announcement. Le Verrier received Lescarbault's letter on December 22, 1859. Although dissatisfied with Lescarbault's crude equipment, Le Verrier was satisfied that the physician had seen the transit of a previously unknown planet. He announced the discovery of 'Vulcan' at the Académie des Sciences in Paris on January 2, 1860.

Controversy and Skepticism. Emmanuel Liais, an eminent French astronomer working in Rio de Janeiro, claimed to have been studying the Sun with a more powerful telescope at the exact moment Lescarbault reported his observation, contradicting the transit claim. Despite this, Le Verrier computed Vulcan's orbit based on Lescarbault's report.